diff --git a/open-sse/handlers/chatCore.ts b/open-sse/handlers/chatCore.ts
index 78e4f11817..b1eabdb92e 100644
--- a/open-sse/handlers/chatCore.ts
+++ b/open-sse/handlers/chatCore.ts
@@ -293,8 +293,9 @@ function estimateSizeFast(value: unknown): number {
       if (Array.isArray(v)) {
         for (let i = 0; i < v.length; i++) stack.push(v[i]);
       } else {
-        const vals = Object.values(v);
-        for (let i = 0; i < vals.length; i++) stack.push(vals[i]);
+        for (const key in v) {
+          if (Object.prototype.hasOwnProperty.call(v, key)) stack.push((v as Record<string, unknown>)[key]);
+        }
       }
     }
   }
@@ -3997,7 +3998,7 @@ export async function handleChatCore({
     (translatedBody.conversationState?.history?.length ?? 0) +
       (translatedBody.conversationState?.currentMessage ? 1 : 0) ||
     0;
-  log?.debug?.("REQUEST", `${provider.toUpperCase()} | ${model} | ${msgCount} msgs`);
+  log?.debug?.("REQUEST", `${provider?.toUpperCase()} | ${model} | ${msgCount} msgs`);
 
   // ── Tier 2: Authoritative per-model/provider token-limit check (provider now resolved) ──
   if (apiKeyInfo?.id) {
@@ -4233,7 +4234,7 @@ export async function handleChatCore({
     };
 
     if (newCredentials?.accessToken || newCredentials?.copilotToken) {
-      log?.info?.("TOKEN", `${provider.toUpperCase()} | refreshed`);
+      log?.info?.("TOKEN", `${provider?.toUpperCase()} | refreshed`);
 
       // Fall back to post-mutex mutation only for executors that don't route
       // through getAccessToken (and therefore never fire onPersist). For
@@ -4287,11 +4288,11 @@ export async function handleChatCore({
         // than the original 401 alone. Surface at error level with sanitization.
         log?.error?.(
           "TOKEN",
-          `${provider.toUpperCase()} | retry after refresh failed: ${sanitizeErrorMessage(retryErr)}`
+          `${provider?.toUpperCase()} | retry after refresh failed: ${sanitizeErrorMessage(retryErr)}`
         );
       }
     } else {
-      log?.warn?.("TOKEN", `${provider.toUpperCase()} | refresh failed`);
+      log?.warn?.("TOKEN", `${provider?.toUpperCase()} | refresh failed`);
       if (isUnrecoverableRefreshError(newCredentials) && onCredentialsRefreshed) {
         await onCredentialsRefreshed({ testStatus: "expired", isActive: false });
       }
@@ -4942,7 +4943,7 @@ export async function handleChatCore({
     const cacheUsageLogMeta = buildCacheUsageLogMeta(usage);
     if (usage && typeof usage === "object") {
       if (traceEnabled) {
-        const msg = `[${new Date().toLocaleTimeString("en-US", { hour12: false, hour: "2-digit", minute: "2-digit" })}] 📊 [USAGE] ${provider.toUpperCase()} | ${formatUsageLog(usage)}${connectionId ? ` | account=${connectionId.slice(0, 8)}...` : ""}`;
+        const msg = `[${new Date().toLocaleTimeString("en-US", { hour12: false, hour: "2-digit", minute: "2-digit" })}] 📊 [USAGE] ${provider?.toUpperCase()} | ${formatUsageLog(usage)}${connectionId ? ` | account=${connectionId.slice(0, 8)}...` : ""}`;
         console.log(`${COLORS.green}${msg}${COLORS.reset}`);
       }
 
diff --git a/open-sse/services/apiKeyRotator.ts b/open-sse/services/apiKeyRotator.ts
index abf2d7ccb5..58a1337f0d 100644
--- a/open-sse/services/apiKeyRotator.ts
+++ b/open-sse/services/apiKeyRotator.ts
@@ -31,7 +31,7 @@ const MAX_CONNECTION_EXTRA_KEYS = 500;
  */
 export function trackConnectionExtraKeys(connectionId: string, extraKeys: string[]): void {
   const validExtras = extraKeys.filter((k) => typeof k === "string" && k.trim().length > 0);
-  if (_connectionExtraKeys.size >= MAX_CONNECTION_EXTRA_KEYS) {
+  if (!_connectionExtraKeys.has(connectionId) && _connectionExtraKeys.size >= MAX_CONNECTION_EXTRA_KEYS) {
     const oldest = _connectionExtraKeys.keys().next().value;
     if (oldest !== undefined) _connectionExtraKeys.delete(oldest);
   }
@@ -276,11 +276,12 @@ export function syncHealthFromDB(connectionId: string, health?: Record<string, K
   if (!health) return;
 
   for (const [keyId, keyHealth] of Object.entries(health)) {
-    if (_keyHealth.size >= MAX_KEY_HEALTH_ENTRIES) {
+    const scopedKey = `${connectionId}:${keyId}`;
+    if (!_keyHealth.has(scopedKey) && _keyHealth.size >= MAX_KEY_HEALTH_ENTRIES) {
       const oldest = _keyHealth.keys().next().value;
       if (oldest !== undefined) _keyHealth.delete(oldest);
     }
-    _keyHealth.set(`${connectionId}:${keyId}`, keyHealth);
+    _keyHealth.set(scopedKey, keyHealth);
   }
 }
 
diff --git a/open-sse/services/codexQuotaFetcher.ts b/open-sse/services/codexQuotaFetcher.ts
index a572485971..ef40c48286 100644
--- a/open-sse/services/codexQuotaFetcher.ts
+++ b/open-sse/services/codexQuotaFetcher.ts
@@ -86,7 +86,7 @@ const MAX_QUOTA_CACHE_ENTRIES = 200;
  * @param meta - Access token and optional workspace ID
  */
 export function registerCodexConnection(connectionId: string, meta: CodexConnectionMeta): void {
-  if (connectionRegistry.size >= MAX_CONNECTIONS) {
+  if (!connectionRegistry.has(connectionId) && connectionRegistry.size >= MAX_CONNECTIONS) {
     const oldestKey = connectionRegistry.keys().next().value;
     if (oldestKey !== undefined) {
       quotaCache.delete(oldestKey);
@@ -124,7 +124,7 @@ function getCodexConnectionMeta(
 
     if (accessToken) {
       const meta = { accessToken, ...(workspaceId ? { workspaceId } : {}) };
-      if (connectionRegistry.size >= MAX_CONNECTIONS) {
+      if (!connectionRegistry.has(connectionId) && connectionRegistry.size >= MAX_CONNECTIONS) {
         const oldestKey = connectionRegistry.keys().next().value;
         if (oldestKey !== undefined) {
           quotaCache.delete(oldestKey);
@@ -212,7 +212,7 @@ export async function fetchCodexQuota(
     if (!quota) return null;
 
     // Store in cache
-    if (quotaCache.size >= MAX_QUOTA_CACHE_ENTRIES) {
+    if (!quotaCache.has(connectionId) && quotaCache.size >= MAX_QUOTA_CACHE_ENTRIES) {
       const oldestCacheKey = quotaCache.keys().next().value;
       if (oldestCacheKey !== undefined) quotaCache.delete(oldestCacheKey);
     }
diff --git a/open-sse/services/combo.ts b/open-sse/services/combo.ts
index a0ddb3646a..511908ebb7 100644
--- a/open-sse/services/combo.ts
+++ b/open-sse/services/combo.ts
@@ -1550,7 +1550,7 @@ async function getQuotaAwareConnectionsForTarget(
             const activeConnections = Array.isArray(connections)
               ? (connections as Array<Record<string, unknown>>)
               : [];
-            if (resetAwareConnectionCache.size >= MAX_RESET_AWARE_CACHE) {
+            if (!resetAwareConnectionCache.has(provider) && resetAwareConnectionCache.size >= MAX_RESET_AWARE_CACHE) {
               const oldest = resetAwareConnectionCache.keys().next().value;
               if (oldest !== undefined) resetAwareConnectionCache.delete(oldest);
             }
@@ -1685,7 +1685,7 @@ async function fetchResetAwareQuotaWithCache({
     const refreshPromise = fetcher(connectionId, connection)
       .then((quota) => {
         if (quota) {
-          if (resetAwareQuotaCache.size >= MAX_RESET_AWARE_CACHE) {
+          if (!resetAwareQuotaCache.has(cacheKey) && resetAwareQuotaCache.size >= MAX_RESET_AWARE_CACHE) {
             const oldest = resetAwareQuotaCache.keys().next().value;
             if (oldest !== undefined) resetAwareQuotaCache.delete(oldest);
           }
@@ -1702,7 +1702,7 @@ async function fetchResetAwareQuotaWithCache({
       .catch((error) => {
         const previous = resetAwareQuotaCache.get(cacheKey);
         if (previous) {
-          if (resetAwareQuotaCache.size >= MAX_RESET_AWARE_CACHE) {
+          if (!resetAwareQuotaCache.has(cacheKey) && resetAwareQuotaCache.size >= MAX_RESET_AWARE_CACHE) {
             const oldest = resetAwareQuotaCache.keys().next().value;
             if (oldest !== undefined) resetAwareQuotaCache.delete(oldest);
           }
@@ -1718,7 +1718,7 @@ async function fetchResetAwareQuotaWithCache({
         return null;
       });
 
-    if (resetAwareQuotaCache.size >= MAX_RESET_AWARE_CACHE) {
+    if (!resetAwareQuotaCache.has(cacheKey) && resetAwareQuotaCache.size >= MAX_RESET_AWARE_CACHE) {
       const oldest = resetAwareQuotaCache.keys().next().value;
       if (oldest !== undefined) resetAwareQuotaCache.delete(oldest);
     }
@@ -1845,7 +1845,7 @@ async function orderTargetsByResetAwareQuota(
   if (tiedTargets.length > 1) {
     const key = `reset-aware:${comboName}`;
     const counter = rrCounters.get(key) || 0;
-    if (rrCounters.size >= MAX_RR_COUNTERS) {
+    if (!rrCounters.has(key) && rrCounters.size >= MAX_RR_COUNTERS) {
       const oldest = rrCounters.keys().next().value;
       if (oldest !== undefined) rrCounters.delete(oldest);
     }
@@ -2008,7 +2008,7 @@ async function orderTargetsByResetWindow(
 
   const key = `reset-window:${comboName}`;
   const counter = rrCounters.get(key) || 0;
-  if (rrCounters.size >= MAX_RR_COUNTERS) {
+  if (!rrCounters.has(key) && rrCounters.size >= MAX_RR_COUNTERS) {
     const oldest = rrCounters.keys().next().value;
     if (oldest !== undefined) rrCounters.delete(oldest);
   }
@@ -3921,7 +3921,7 @@ async function handleRoundRobinCombo({
 
   // Get and increment atomic counter
   const counter = rrCounters.get(combo.name) || 0;
-  if (rrCounters.size >= MAX_RR_COUNTERS) {
+  if (!rrCounters.has(combo.name) && rrCounters.size >= MAX_RR_COUNTERS) {
     const oldest = rrCounters.keys().next().value;
     if (oldest !== undefined) rrCounters.delete(oldest);
   }