diff --git a/test/scripts/test-group-report.test.ts b/test/scripts/test-group-report.test.ts
index 315ef9f812c0..1cc8ba9ff7ed 100644
--- a/test/scripts/test-group-report.test.ts
+++ b/test/scripts/test-group-report.test.ts
@@ -1107,10 +1107,14 @@ describe("scripts/test-group-report child process guard", () => {
     let childPid: number | undefined;
     let runner: ReturnType<typeof spawn> | undefined;
     try {
+      // Publish the pid via rename so it appears atomically: waitForFile polls
+      // existence only, and a direct writeFileSync leaves an empty-file window
+      // that made the pid parse as NaN (isProcessAlive false) on loaded CI.
       const childScript = [
         "const fs = require('node:fs');",
         "process.on('SIGTERM', () => {});",
-        `fs.writeFileSync(${JSON.stringify(childPidPath)}, String(process.pid));`,
+        `fs.writeFileSync(${JSON.stringify(`${childPidPath}.tmp`)}, String(process.pid));`,
+        `fs.renameSync(${JSON.stringify(`${childPidPath}.tmp`)}, ${JSON.stringify(childPidPath)});`,
         "setInterval(() => {}, 1000);",
       ].join("\n");
       const parentScript = [
@@ -1133,8 +1137,10 @@ describe("scripts/test-group-report child process guard", () => {
         cwd: process.cwd(),
         stdio: ["ignore", "ignore", "pipe"],
       });
-      await waitForFile(readyPath, 2_000);
-      await waitForFile(childPidPath, 2_000);
+      // Generous poll deadlines: spawning the nested runner/parent/child node
+      // chain can take multiple seconds on loaded CI runners.
+      await waitForFile(readyPath, 10_000);
+      await waitForFile(childPidPath, 10_000);
       childPid = Number.parseInt(fs.readFileSync(childPidPath, "utf8"), 10);
       expect(isProcessAlive(childPid)).toBe(true);
 
@@ -1144,7 +1150,7 @@ describe("scripts/test-group-report child process guard", () => {
         code: null,
         signal: "SIGTERM",
       });
-      await waitForDead(childPid, 2_000);
+      await waitForDead(childPid, 10_000);
     } finally {
       if (runner?.pid && isProcessAlive(runner.pid)) {
         runner.kill("SIGKILL");