diff --git a/src/authorization/AuthorizationChecker.js b/src/authorization/AuthorizationChecker.js
index 39f65f0..96396e0 100644
--- a/src/authorization/AuthorizationChecker.js
+++ b/src/authorization/AuthorizationChecker.js
@@ -86,7 +86,8 @@ export class AuthorizationChecker {
       // Check cache first using composite key (if caching is enabled)
       let cachedResult = null;
       let cacheHint = null;
-      if (!hasPartialGraph && this.decisionCache.directEnabled && !includeMeta) {
+      const temporalPinned = options.now !== undefined && options.now !== null;
+      if (!hasPartialGraph && this.decisionCache.directEnabled && !includeMeta && !temporalPinned) {
         const cacheKey = this._getDirectCheckCacheKey(userKey, relation, objectKey);
         const [hitResult, status] = this.decisionCache.peekDirect(cacheKey);
         cachedResult = status === 'hit' || status === 'expired' ? { result: hitResult, timestamp: 0 } : null;
@@ -112,8 +113,9 @@ export class AuthorizationChecker {
         };
         
         // Cache the result (only when no partial graph and the default
-        // meta-less form — includeMeta callers get a fresh full evaluation)
-        if (!explain && !hasPartialGraph && !includeMeta) {
+        // meta-less form — includeMeta callers and pinned-clock callers get
+        // a fresh evaluation)
+        if (!explain && !hasPartialGraph && !includeMeta && !temporalPinned) {
           this._cacheDirectCheckResult(userKey, relation, objectKey, result);
         }
         return result;
@@ -227,7 +229,7 @@ export class AuthorizationChecker {
       }
       
       // Cache the result using composite key (meta-less form only)
-      if (!explain && !hasPartialGraph && !includeMeta) {
+      if (!explain && !hasPartialGraph && !includeMeta && !temporalPinned) {
         this._cacheDirectCheckResult(userKey, relation, objectKey, result);
       }
       return result;
@@ -264,8 +266,9 @@ export class AuthorizationChecker {
       };
     }
 
+    const temporalPinned = options.now !== undefined && options.now !== null;
     const canCacheRuleResult = !hasPartialGraph && !explain && !includeMeta &&
-      !binary && options.cacheRuleResult !== false && this.decisionCache.ruleEnabled;
+      !binary && !temporalPinned && options.cacheRuleResult !== false && this.decisionCache.ruleEnabled;
     const ruleCacheKey = canCacheRuleResult
       ? this._getRuleResultCacheKey(userId, relation, objectId)
       : null;
diff --git a/src/authorization/RuleEvaluator.js b/src/authorization/RuleEvaluator.js
index b2153b7..8cba107 100644
--- a/src/authorization/RuleEvaluator.js
+++ b/src/authorization/RuleEvaluator.js
@@ -43,8 +43,11 @@ export class RuleEvaluator {
     const collectValues = options.collectValues !== undefined ? options.collectValues : (rule._needsValues ?? needsValueContext);
     const enhancedOptions = { ...options, minPossibility: options.minPossibility ?? options.minAllowPossibility, valueContext: finalValueContext, collectValues, includeMeta };
 
+    // A caller-pinned clock (options.now) makes the result per-clock: the
+    // result caches must not serve a decision evaluated at another time.
+    const temporalPinned = options.now !== undefined && options.now !== null;
     const canCacheRuleResult = !!this.arbiter.ruleResultCache && currentRelation &&
-      !binary && !options.partialGraphContext && !includeMeta &&
+      !binary && !options.partialGraphContext && !includeMeta && !temporalPinned &&
       options.cacheRuleResult !== false;
     const ruleCacheKey = canCacheRuleResult
       ? this._getRuleResultCacheKey(numericUserId, currentRelation, numericObjectId, rule)
diff --git a/src/authorization/rules/ChallengeRule.js b/src/authorization/rules/ChallengeRule.js
index 3c34613..69798bb 100644
--- a/src/authorization/rules/ChallengeRule.js
+++ b/src/authorization/rules/ChallengeRule.js
@@ -28,7 +28,7 @@ export class ChallengeRule extends BaseRule {
     }
 
     const subjectId = this.arbiter.resolveNodeId(subjectKey, { partialGraphContext: partialContext });
-    const now = Date.now();
+    const now = options.now !== undefined && options.now !== null ? options.now : Date.now();
     const proof = partialContext.getChallengeProof(challenge, subjectId, withinMs, now);
 
     if (!proof) {
diff --git a/src/authorization/rules/MultiHopRule.js b/src/authorization/rules/MultiHopRule.js
index 84b26db..f036e2f 100644
--- a/src/authorization/rules/MultiHopRule.js
+++ b/src/authorization/rules/MultiHopRule.js
@@ -349,8 +349,9 @@ export class MultiHopRule extends BaseRule {
    * Collect values from a complete path
    * @private
    */
-  _collectValuesFromPath(pathSteps, defaultRelation, valueFilters, valueContext) {
+  _collectValuesFromPath(pathSteps, defaultRelation, valueFilters, valueContext, options = null) {
     const collectedValues = [];
+    const evaluationNow = options && options.now !== undefined && options.now !== null ? options.now : Date.now();
     // Get blurred interval from ValueManager (arbiter-level; some stubs and
     // older layouts keep it on the relation manager)
     const valueManager = this.arbiter.valueManager || this.arbiter.relationManager?.valueManager;
@@ -373,7 +374,7 @@ export class MultiHopRule extends BaseRule {
             const ttl = valueFilters.ttl || 24 * 60 * 60 * 1000;
             const timestamp = step.edge.changed_last_at || step.edge.updated_last_at || Date.now();
             
-            if (!OWAFusion.isWithinTTL(timestamp, ttl)) {
+            if (!OWAFusion.isWithinTTL(timestamp, ttl, evaluationNow)) {
               Arbiter.DEBUG && Arbiter.log('MultiHop skipping value due to TTL:', {
                 value: step.edge.value,
                 timestamp,
@@ -431,7 +432,7 @@ export class MultiHopRule extends BaseRule {
             if (this._passesValueFilters(contextValue.value, valueFilters)) {
               // Check TTL
               const ttl = valueFilters.ttl || 24 * 60 * 60 * 1000;
-              if (!OWAFusion.isWithinTTL(contextValue.timestamp, ttl)) {
+              if (!OWAFusion.isWithinTTL(contextValue.timestamp, ttl, evaluationNow)) {
                 continue;
               }
               
diff --git a/src/authorization/rules/RelationalComparatorRule.js b/src/authorization/rules/RelationalComparatorRule.js
index 95e7bd6..87f247c 100644
--- a/src/authorization/rules/RelationalComparatorRule.js
+++ b/src/authorization/rules/RelationalComparatorRule.js
@@ -148,6 +148,7 @@ export class RelationalComparatorRule extends BaseRule {
     const resolvedRule = operandCompiled?.rule || nestedRuleConfig;
     const { valueContext = null } = options;
 
+    const evaluationNow = options.now !== undefined && options.now !== null ? options.now : Date.now();
     const operandMetaBase = {
         operandSide: side,
         nestedRuleType: resolvedRule?.type || nestedRuleConfig.type,
@@ -215,6 +216,7 @@ export class RelationalComparatorRule extends BaseRule {
 
     const canCacheDerived = extractValue && !!this.arbiter.ruleResultCache &&
       !options.partialGraphContext && !options.includeMeta &&
+      (options.now === undefined || options.now === null) &&
       options.cacheDerivedValues !== false;
     const operandIdentity = this._getOperandCacheIdentity(resolvedValueRelation, resolvedRule, nestedRuleConfig);
     const derivedCacheKey = canCacheDerived
@@ -282,7 +284,7 @@ export class RelationalComparatorRule extends BaseRule {
       let operandSource = null;
 
       if (directRel && typeof directRel.value === 'number') {
-        const cached = this._getCachedDirectValue(directRel, ttl);
+        const cached = this._getCachedDirectValue(directRel, ttl, evaluationNow);
         if (cached) {
           const aggregatedResult = this._aggregateCrispValues(
             [cached], finalAggregator, owaWeights, operandEvalMeta, options
@@ -389,7 +391,7 @@ export class RelationalComparatorRule extends BaseRule {
         }
         const rel = this.arbiter.relationManager.getDirectRelation(srcId, relName, dstId, options);
         if (!rel || typeof rel.value !== 'number') continue;
-        if (this.arbiter.valueManager && this.arbiter.valueManager._isValueExpired(rel)) continue;
+        if (this.arbiter.valueManager && this.arbiter.valueManager._isValueExpired(rel, evaluationNow)) continue;
 
         valueResults.push({
           value: rel.value,
@@ -615,7 +617,7 @@ export class RelationalComparatorRule extends BaseRule {
    */
   _extractValues(userId, userKey, objectId, objectKey, rule, valueRelation, ruleResult, evaluateFrom, valueContext, ttl, operandEvalMeta, options = null) {
     const results = [];
-    const now = Date.now();
+    const now = options && options.now !== undefined && options.now !== null ? options.now : Date.now();
     const ttlCutoff = now - ttl;
     
     // First check if rule result directly provides values
@@ -698,7 +700,7 @@ export class RelationalComparatorRule extends BaseRule {
       if (rule.type === 'direct') {
         const directRel = this._getDirectRelationForValue(userId, objectId, relationName, evaluateFrom, options);
         if (directRel && typeof directRel.value === 'number') {
-          const cached = this._getCachedDirectValue(directRel, ttl);
+          const cached = this._getCachedDirectValue(directRel, ttl, now);
           if (cached) {
             results.push(cached);
           }
@@ -782,8 +784,9 @@ export class RelationalComparatorRule extends BaseRule {
     return directRel;
   }
 
-  _getCachedDirectValue(relation, ttl) {
-    if (this.arbiter.valueManager && this.arbiter.valueManager._isValueExpired(relation)) {
+  _getCachedDirectValue(relation, ttl, now = null) {
+    const ts = now !== null && now !== undefined ? now : Date.now();
+    if (this.arbiter.valueManager && this.arbiter.valueManager._isValueExpired(relation, ts)) {
       return null;
     }
     const cacheKey = `${relation.src}|${relation.rel}|${relation.dst}`;
@@ -791,8 +794,8 @@ export class RelationalComparatorRule extends BaseRule {
     if (cached && cached.stateId === relation.stateId) {
       return cached;
     }
-    const timestamp = relation.changed_last_at || relation.updated_last_at || Date.now();
-    if (!OWAFusion.isWithinTTL(timestamp, ttl)) {
+    const timestamp = relation.changed_last_at || relation.updated_last_at || ts;
+    if (!OWAFusion.isWithinTTL(timestamp, ttl, ts)) {
       return null;
     }
     const entry = {
diff --git a/src/core/ExplainSerializer.js b/src/core/ExplainSerializer.js
index ec847d4..0776f7e 100644
--- a/src/core/ExplainSerializer.js
+++ b/src/core/ExplainSerializer.js
@@ -71,6 +71,13 @@ export class ExplainSerializer {
       }
     };
 
+    // Temporal context: the explain rerun must reproduce the original
+    // decision, so the temporal parameters (now, the TTL/proof clock) are
+    // recorded here — the caller replays them verbatim on the rerun.
+    if (options && options.now !== undefined && options.now !== null) {
+      request.temporal = { now: options.now };
+    }
+
     if (redaction === 'hash') {
       request.userKeyHash = this._hashKey(userKey);
       request.objectKeyHash = this._hashKey(objectKey);
diff --git a/src/core/ValueManager.js b/src/core/ValueManager.js
index d690cd8..d709b03 100644
--- a/src/core/ValueManager.js
+++ b/src/core/ValueManager.js
@@ -159,10 +159,11 @@ export class ValueManager {
    * Check if a relation value has expired based on TTL
    * @private
    */
-  _isValueExpired(relation) {
+  _isValueExpired(relation, now = null) {
     const ttl = this.getTTL(relation.rel);
-    const timestamp = relation.changed_last_at || relation.updated_last_at || Date.now();
-    const age = Date.now() - timestamp;
+    const ts = now !== null && now !== undefined ? now : Date.now();
+    const timestamp = relation.changed_last_at || relation.updated_last_at || ts;
+    const age = ts - timestamp;
     return age > ttl;
   }
 
diff --git a/src/utils/OWAFusion.js b/src/utils/OWAFusion.js
index 47e00d5..f7134b4 100644
--- a/src/utils/OWAFusion.js
+++ b/src/utils/OWAFusion.js
@@ -1012,9 +1012,9 @@ export class OWAFusion {
    * @param {number} ttlMs - TTL in milliseconds (default 24 hours)
    * @returns {boolean} Whether the value is within TTL
    */
-  static isWithinTTL(timestamp, ttlMs = 24 * 60 * 60 * 1000) {
+  static isWithinTTL(timestamp, ttlMs = 24 * 60 * 60 * 1000, now = null) {
     if (!timestamp) return false;
-    const age = Date.now() - timestamp;
+    const age = (now !== null && now !== undefined ? now : Date.now()) - timestamp;
     return age <= ttlMs;
   }
   
diff --git a/tests/rigor/validity-parity.test.js b/tests/rigor/validity-parity.test.js
index 99d9b8e..8019129 100644
--- a/tests/rigor/validity-parity.test.js
+++ b/tests/rigor/validity-parity.test.js
@@ -243,3 +243,49 @@ describe('Persistence losslessness (rigor)', () => {
     assert.equal(restored2.relationManager.getDirectRelation(restored2.resolveNodeId('u:0'), 'owner', restored2.resolveNodeId('d:0')).validity, 'finite_sample');
   });
 });
+
+describe('Temporal replay (re-entrant diagnostics) (rigor)', () => {
+  it('FIXED: pinned-clock checks are per-time, and the explain rerun reproduces the decision', () => {
+    const a = new Arbiter();
+    a.addNode('u:0', 'user');
+    a.addNode('d:0', 'doc');
+    a.setRelationConfig('premium', {
+      type: 'relational_comparator', comparator: '>',
+      left: { rule: { type: 'direct', relation: 'has_balance' }, extractValue: true },
+      right: { evaluateFrom: 'object', rule: { type: 'direct', relation: 'has_price' }, extractValue: true }
+    });
+    a.valueManager.setTTL('has_balance', 60000);
+    a.valueManager.setTTL('has_price', 60000);
+    const t0 = 1000000;
+    a.addRelation('u:0', 'has_balance', 'd:0', { value: 100, changed_last_at: t0 });
+    a.addRelation('d:0', 'has_price', 'd:0', { value: 50, changed_last_at: t0 });
+
+    // Interleaved pinned-clock checks must each reflect their own clock —
+    // no cross-contamination through any result cache.
+    assert.equal(a.check('u:0', 'premium', 'd:0', { now: t0 + 120000 }).possibility, 0, 'expired at +120s');
+    assert.equal(a.check('u:0', 'premium', 'd:0', { now: t0 + 1000 }).possibility, 1, 'fresh at +1s');
+    assert.equal(a.check('u:0', 'premium', 'd:0', { now: t0 + 120000 }).possibility, 0, 'expired again');
+
+    // The explain rerun reproduces the pinned decision and records the
+    // temporal context the caller must replay.
+    const e = a.explain('u:0', 'premium', 'd:0', { now: t0 + 120000 });
+    assert.equal(e.decision.possibility, 0, 'explain rerun reproduces the expired decision');
+    assert.deepEqual(e.request.temporal, { now: t0 + 120000 }, 'temporal context recorded for replay');
+    const e2 = a.explain('u:0', 'premium', 'd:0', { now: t0 + 1000 });
+    assert.equal(e2.decision.possibility, 1, 'explain rerun reproduces the fresh decision');
+  });
+
+  it('FIXED: challenge proof expiry is replayable via the pinned clock', () => {
+    const a = new Arbiter();
+    a.addNode('u:0', 'user');
+    a.addNode('d:0', 'doc');
+    a.setRelationConfig('can_download', { type: 'challenge', challenge: 'mfa', subject: 'user', withinMinutes: 5 });
+    const issued = 500000;
+    const proof = [{ name: 'mfa', subject: 'u:0', issuedAt: issued, expiresAt: null }];
+    assert.equal(a.check('u:0', 'can_download', 'd:0', { partialGraph: { challenges: proof }, now: issued + 299000 }).possibility, 1, 'within window');
+    assert.equal(a.check('u:0', 'can_download', 'd:0', { partialGraph: { challenges: proof }, now: issued + 301000 }).possibility, 0, 'past window');
+    const e = a.explain('u:0', 'can_download', 'd:0', { partialGraph: { challenges: proof }, now: issued + 301000 });
+    assert.equal(e.decision.possibility, 0, 'explain reproduces the expired proof');
+    assert.deepEqual(e.request.temporal, { now: issued + 301000 }, 'challenge temporal recorded');
+  });
+});