diff --git a/src/hooks/bundled/session-memory/handler.ts b/src/hooks/bundled/session-memory/handler.ts
index e9aea24aa20..323ed371e71 100644
--- a/src/hooks/bundled/session-memory/handler.ts
+++ b/src/hooks/bundled/session-memory/handler.ts
@@ -332,7 +332,7 @@ const saveSessionToMemory: HookHandler = async (event) => {
     // one silently overwrites the earlier memory entry.
     if (!slug) {
       const timeSlug = now.toISOString().split("T")[1].split(".")[0].replace(/:/g, "");
-      const rand = Math.random().toString(36).slice(2, 6); // 4-char alphanumeric
+      const rand = Math.random().toString(36).slice(2, 6) || "0000"; // 4-char alphanumeric
       slug = `${timeSlug.slice(0, 6)}-${rand}`;
       log.debug("Using fallback timestamp slug", { slug });
     }
@@ -439,11 +439,12 @@ const saveSessionToMemory: HookHandler = async (event) => {
             await fs.unlink(memoryFilePath);
             log.debug("Session save retracted by post-hook (blockSessionSave)");
           } catch (err) {
-            // ENOENT is expected when the inline write didn't happen
-            // (e.g. blockSessionSave was set before writeFileWithinRoot).
-            // Re-throw so triggerInternalHook logs it. Note: the error
-            // is caught per-action and does NOT propagate to the caller;
-            // the file may remain on disk if unlink fails (e.g. EACCES).
+            // ENOENT can occur if the file was externally deleted between
+            // the inline write and the post-hook drain — not a concern.
+            // Re-throw non-ENOENT errors (e.g. EACCES, EROFS) so
+            // triggerInternalHook logs them. Note: errors are caught
+            // per-action and do NOT propagate to the session caller;
+            // the file may remain on disk under adversarial FS conditions.
             if ((err as NodeJS.ErrnoException).code !== "ENOENT") {
               throw err;
             }
diff --git a/src/hooks/internal-hooks.ts b/src/hooks/internal-hooks.ts
index 1d02a4aa2b3..4dcf3040d89 100644
--- a/src/hooks/internal-hooks.ts
+++ b/src/hooks/internal-hooks.ts
@@ -292,7 +292,13 @@ export async function triggerInternalHook(event: InternalHookEvent): Promise<voi
   // a chance to mutate event.context, eliminating FIFO ordering issues.
   // Actions execute in push order; errors are caught per-action so one
   // failure doesn't block others.
-  for (const action of event.postHookActions) {
+  //
+  // Snapshot the array before draining so that actions pushed *by* post-hook
+  // callbacks do not execute in this drain cycle. Without this, a self-
+  // scheduling action (one that pushes another action) could loop infinitely
+  // because Array's for...of iterator is live and re-reads length each step.
+  const pendingActions = [...(event.postHookActions ?? [])];
+  for (const action of pendingActions) {
     try {
       await action();
     } catch (err) {