Intermittent FAIL in /fetch/fetch-later/permissions-policy/deferred-fetch-allowed-by-permissions-policy.https.window.html #40478

OK /fetch/fetch-later/permissions-policy/deferred-fetch-allowed-by-permissions-policy.https.window.html
  │   ▶ FAIL [expected PASS] Permissions policy header: "deferred-fetch=*" allows fetchLater() in the top-level document.
  │   │   → assert_equals: Number of sent beacons does not match expected count: expected 1 but got 0
  │   │ 
  │   │ expectBeacon@https://web-platform.test:8443/fetch/fetch-later/resources/fetch-later-helper.js:165:18
  │   │ async*@https://web-platform.test:8443/fetch/fetch-later/permissions-policy/deferred-fetch-allowed-by-permissions-policy.https.window.js:24:9
  │   │ parallelPromiseTest/<@https://web-platform.test:8443/fetch/fetch-later/resources/fetch-later-helper.js:11:21
  │   │ Test.prototype.step@https://web-platform.test:8443/resources/testharness.js:2869:25
  │   │ async_test@https://web-platform.test:8443/resources/testharness.js:681:34
  │   │ parallelPromiseTest@https://web-platform.test:8443/fetch/fetch-later/resources/fetch-later-helper.js:10:13
  └   └ @https://web-platform.test:8443/fetch/fetch-later/permissions-policy/deferred-fetch-allowed-by-permissions-policy.https.window.js:17:20