diff --git a/extensions/zalouser/src/zalo-js.credentials.test.ts b/extensions/zalouser/src/zalo-js.credentials.test.ts
index 3172b085161..a7036010124 100644
--- a/extensions/zalouser/src/zalo-js.credentials.test.ts
+++ b/extensions/zalouser/src/zalo-js.credentials.test.ts
@@ -1,4 +1,14 @@
-import { lstat, mkdir, mkdtemp, readFile, rm, stat, symlink, writeFile } from "node:fs/promises";
+import {
+  lstat,
+  mkdir,
+  mkdtemp,
+  readFile,
+  rm,
+  stat,
+  symlink,
+  utimes,
+  writeFile,
+} from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
 import { withEnvAsync } from "openclaw/plugin-sdk/test-env";
@@ -7,7 +17,6 @@ import type { API, Credentials, LoginQRCallbackEvent } from "./zca-client.js";
 import { LoginQRCallbackEventType } from "./zca-constants.js";
 
 const createZaloMock = vi.hoisted(() => vi.fn());
-const TEST_MTIME_TICK_MS = 20;
 const ISO_TIMESTAMP_RE = /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}Z$/u;
 
 vi.mock("./zca-client.js", () => ({
@@ -51,10 +60,6 @@ async function readStoredCredentials(
   ) as StoredCredentialFile;
 }
 
-async function waitForMtimeTick(): Promise<void> {
-  await new Promise((resolve) => setTimeout(resolve, TEST_MTIME_TICK_MS));
-}
-
 function createMockApi(params: {
   imei: string;
   userAgent: string;
@@ -308,10 +313,11 @@ describe("zalouser credential persistence", () => {
       await withEnvAsync({ OPENCLAW_STATE_DIR: stateDir }, async () => {
         await expect(listZaloFriends(profile)).resolves.toEqual([]);
         const firstRaw = await readFile(filePath, "utf8");
+        const stableMtime = new Date("2026-04-01T00:00:10.000Z");
+        await utimes(filePath, stableMtime, stableMtime);
         const firstMtimeMs = (await stat(filePath)).mtimeMs;
 
         currentCookie = cookieB;
-        await waitForMtimeTick();
 
         await expect(listZaloFriends(profile)).resolves.toEqual([]);
         expect(await readFile(filePath, "utf8")).toBe(firstRaw);