User reports: Sometimes reddit(or other sites) content will disappear, becomes a white page and the browser proceeds to flash like some rave party. After reloading the affected page, the issue is gone.

https://www.reddit.com/r/firefox/comments/bva4pt/reddit_flashing_new_pages_not_loading_sometimes/

about:support attached

Andrew, can you help see if you can reproduce this on Monday?

Actually, I will see if Sotaro can take a look at this Monday his time :)

OK, I take a look it the bug is reproducible.

Bug 1555544 caused heavy flickering of WebGL background during removing and adding the canvas node every frame. But normal reddit page did not have such background.

(In reply to Sotaro Ikeda [:sotaro] from comment #3)

OK, I take a look it the bug is reproducible.

Hmm, I could not reproduce the problem.

Bug 1556340 might be related to the problem, though I could not reproduce the problem.

Hey Dan - I see you were able to reproduce Bug 1555544 - can you take a quick peak to see if you can reproduce the issue described here too? Trying to determine how big of an issue it really is. Thank you!

I wonder if this line from about:support might be relevant?

Target Frame Rate: 144

Is it possible that might be breaking some assumptions in the Gecko / WR integration? Or perhaps be relevant to reproducing the issue?

From reddit: "It is not reproducable, and it only happens roughly once a day. It is very random, sadly."

(In reply to Jessie [:jbonisteel] plz needinfo from comment #7)

Hey Dan - I see you were able to reproduce Bug 1555544 - can you take a quick peak to see if you can reproduce the issue described here too? Trying to determine how big of an issue it really is. Thank you!

I was unable to reproduce the flashing rave party on reddit.com. My whole laptop did lockup though. Unclear if that's related, or not.

Marking this is P3 for now since we can't reproduce and the reporter on Reddit also says it happens inconsistently. Will re-evaluate priority if that changes.

Not tracking for now.

We don't have a clear way to make progress here. Unblocking.