Filed by: btara [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer?job_id=320491386&repo=autoland
Full log: https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/ehR-ynWxS56Rj-RbzhioVA/runs/0/artifacts/public/logs/live_backing.log
Reftest URL: https://hg.mozilla.org/mozilla-central/raw-file/tip/layout/tools/reftest/reftest-analyzer.xhtml#logurl=https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/ehR-ynWxS56Rj-RbzhioVA/runs/0/artifacts/public/logs/live_backing.log&only_show_unexpected=1

[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST TEST-START | layout/reftests/transform-3d/preserve3d-will-change-large-frame.html == layout/reftests/transform-3d/preserve3d-will-change-ref.html
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST TEST-LOAD | http://10.7.205.239:8854/tests/layout/reftests/transform-3d/preserve3d-will-change-large-frame.html | 2155 / 2157 (99%)
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST TEST-LOAD | http://10.7.205.239:8854/tests/layout/reftests/transform-3d/preserve3d-will-change-ref.html | 2155 / 2157 (99%)
[task 2020-11-02T17:58:00.203Z] 17:58:00  WARNING -  REFTEST TEST-UNEXPECTED-FAIL | layout/reftests/transform-3d/preserve3d-will-change-large-frame.html == layout/reftests/transform-3d/preserve3d-will-change-ref.html | image comparison, max difference: 252, number of differing pixels: 800000
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST   IMAGE 1 (TEST): data:image/png;base64,iVBORw0KGgoAAAANSUh...
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST   IMAGE 2 (REFERENCE): data:image/png;base64,iVBORw0KGg...
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST INFO | Saved log: START http://10.7.205.239:8854/tests/layout/reftests/transform-3d/preserve3d-will-change-large-frame.html
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST INFO | Saved log: [CONTENT] OnDocumentLoad triggering AfterOnLoadScripts
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST INFO | Saved log: Initializing canvas snapshot
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST INFO | Saved log: DoDrawWindow 0,0,800,1000
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST INFO | Saved log: [CONTENT] RecordResult fired
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST INFO | Saved log: RecordResult fired
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST INFO | Saved log: START http://10.7.205.239:8854/tests/layout/reftests/transform-3d/preserve3d-will-change-ref.html
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST INFO | Saved log: [CONTENT] OnDocumentLoad triggering AfterOnLoadScripts
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST INFO | Saved log: Initializing canvas snapshot
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST INFO | Saved log: DoDrawWindow 0,0,800,1000
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST INFO | Saved log: [CONTENT] RecordResult fired
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST INFO | Saved log: RecordResult fired
[task 2020-11-02T17:58:00.203Z] 17:58:00     INFO -  REFTEST TEST-END | layout/reftests/transform-3d/preserve3d-will-change-large-frame.html == layout/reftests/transform-3d/preserve3d-will-change-ref.html

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