Parsed log: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=319978298&repo=autoland&lineNumber=1486
Full log: https://firefoxci.taskcluster-artifacts.net/XADQA0yzRYaFtgzXs-hoYw/0/public/logs/live_backing.log

Log snippet:

[task 2020-10-28T09:53:01.516Z] 09:53:01     INFO - TEST-START | /paint-timing/fcp-only/fcp-ignore-from-subframe.html
[task 2020-10-28T09:53:01.516Z] 09:53:01     INFO - Run 0/10
[task 2020-10-28T09:53:01.836Z] 09:53:01     INFO - 
[task 2020-10-28T09:53:01.836Z] 09:53:01     INFO - TEST-UNEXPECTED-PASS | /paint-timing/fcp-only/fcp-ignore-from-subframe.html | Parent frame should not fire own paint-timing events for subframes. - expected FAIL
[task 2020-10-28T09:53:01.836Z] 09:53:01     INFO - TEST-INFO | expected FAIL
[task 2020-10-28T09:53:01.836Z] 09:53:01     INFO - TEST-OK | /paint-timing/fcp-only/fcp-ignore-from-subframe.html | took 324ms
[task 2020-10-28T09:53:01.844Z] 09:53:01     INFO - PID 1195 | 1603878781838	Marionette	INFO	Stopped listening on port 37169
[task 2020-10-28T09:53:02.252Z] 09:53:02     INFO - Browser exited with return code 0
[task 2020-10-28T09:53:02.252Z] 09:53:02     INFO - PROCESS LEAKS None
[task 2020-10-28T09:53:02.252Z] 09:53:02     INFO - Closing logging queue
[task 2020-10-28T09:53:02.253Z] 09:53:02     INFO - queue closed
[task 2020-10-28T09:53:02.269Z] 09:53:02     INFO - Application command: /builds/worker/workspace/build/application/firefox/firefox --marionette about:blank -profile /tmp/tmpfPRZFp
[task 2020-10-28T09:53:02.277Z] 09:53:02     INFO - Starting runner
[task 2020-10-28T09:53:04.290Z] 09:53:04     INFO - PID 1467 | console.warn: SearchSettings: "get: No settings file exists, new profile?" (new Error("", "(unknown module)"))
[task 2020-10-28T09:53:05.022Z] 09:53:05     INFO - PID 1467 | 1603878785019	Marionette	INFO	Listening on port 55955
[task 2020-10-28T09:53:05.214Z] 09:53:05     INFO - TEST-START | /paint-timing/fcp-only/fcp-ignore-from-subframe.html
[task 2020-10-28T09:53:05.214Z] 09:53:05     INFO - Run 1/10
[task 2020-10-28T09:53:05.480Z] 09:53:05     INFO - 
[task 2020-10-28T09:53:05.480Z] 09:53:05     INFO - TEST-UNEXPECTED-PASS | /paint-timing/fcp-only/fcp-ignore-from-subframe.html | Parent frame should not fire own paint-timing events for subframes. - expected FAIL
[task 2020-10-28T09:53:05.481Z] 09:53:05     INFO - TEST-INFO | expected FAIL
[task 2020-10-28T09:53:05.481Z] 09:53:05     INFO - TEST-OK | /paint-timing/fcp-only/fcp-ignore-from-subframe.html | took 269ms
[task 2020-10-28T09:53:05.488Z] 09:53:05     INFO - PID 1467 | 1603878785484	Marionette	INFO	Stopped listening on port 55955
[task 2020-10-28T09:53:05.896Z] 09:53:05     INFO - Browser exited with return code 0
[task 2020-10-28T09:53:05.896Z] 09:53:05     INFO - PROCESS LEAKS None
[task 2020-10-28T09:53:05.896Z] 09:53:05     INFO - Closing logging queue
[task 2020-10-28T09:53:05.896Z] 09:53:05     INFO - queue closed
[task 2020-10-28T09:53:05.912Z] 09:53:05     INFO - Application command: /builds/worker/workspace/build/application/firefox/firefox --marionette about:blank -profile /tmp/tmpK_Pc3f
[task 2020-10-28T09:53:05.919Z] 09:53:05     INFO - Starting runner
[task 2020-10-28T09:53:07.965Z] 09:53:07     INFO - PID 1698 | console.warn: SearchSettings: "get: No settings file exists, new profile?" (new Error("", "(unknown module)"))
[task 2020-10-28T09:53:08.620Z] 09:53:08     INFO - PID 1698 | 1603878788616	Marionette	INFO	Listening on port 56138
[task 2020-10-28T09:53:08.754Z] 09:53:08     INFO - TEST-START | /paint-timing/fcp-only/fcp-ignore-from-subframe.html
[task 2020-10-28T09:53:08.756Z] 09:53:08     INFO - Run 2/10
[task 2020-10-28T09:53:09.028Z] 09:53:09     INFO - 
[task 2020-10-28T09:53:09.028Z] 09:53:09     INFO - TEST-UNEXPECTED-PASS | /paint-timing/fcp-only/fcp-ignore-from-subframe.html | Parent frame should not fire own paint-timing events for subframes. - expected FAIL
[task 2020-10-28T09:53:09.028Z] 09:53:09     INFO - TEST-INFO | expected FAIL
[task 2020-10-28T09:53:09.028Z] 09:53:09     INFO - TEST-OK | /paint-timing/fcp-only/fcp-ignore-from-subframe.html | took 271ms
[task 2020-10-28T09:53:09.043Z] 09:53:09     INFO - PID 1698 | 1603878789031	Marionette	INFO	Stopped listening on port 56138
[task 2020-10-28T09:53:09.443Z] 09:53:09     INFO - Browser exited with return code 0
[task 2020-10-28T09:53:09.443Z] 09:53:09     INFO - PROCESS LEAKS None
[task 2020-10-28T09:53:09.445Z] 09:53:09     INFO - Closing logging queue
[task 2020-10-28T09:53:09.446Z] 09:53:09     INFO - queue closed
[task 2020-10-28T09:53:09.462Z] 09:53:09     INFO - Application command: /builds/worker/workspace/build/application/firefox/firefox --marionette about:blank -profile /tmp/tmpx72bmv
[task 2020-10-28T09:53:09.477Z] 09:53:09     INFO - Starting runner
[task 2020-10-28T09:53:11.566Z] 09:53:11     INFO - PID 1934 | console.warn: SearchSettings: "get: No settings file exists, new profile?" (new Error("", "(unknown module)"))
[task 2020-10-28T09:53:12.205Z] 09:53:12     INFO - PID 1934 | 1603878792193	Marionette	INFO	Listening on port 49053

Set release status flags based on info from the regressing bug 1673581

https://wiki.mozilla.org/Bug_Triage#Intermittent_Test_Failure_Cleanup
For more information, please visit auto_nag documentation.