This is a discussion topic for the following Common Issue:
You can discuss the problem and its solutions here, but please note that debugging and technical feedback should primarily go to the issue trackers (e.g. Bugzilla) linked in the Common Issue, because that’s the place that developers watch, not here.
If there are any updates/changes/amendments for the Common Issue description, which you believe should be performed, please post it here.
Please see the Common Issue for solution/workarounds:
Otherwise, no clear workaround is known - all you can do is quit Firefox and restart when the problems appear.
Why does this topic have a solution when there is no clear Workaround/Solution known?
I might write some FAQ entry about this somewhere, because you’re not the first one to ask 
I don’t know how to structure these “Talk” threads better (than what I do right now). Without the “Solution” mark, people had no idea that this is actually just a discussion thread for a problem documented in detail elsewhere (basically, they skipped the first post without clicking on the link). The Solution makes them realize (and Discourse also reminds them when posting a reply) that there’s a highlighted post, and that makes them realize that there’s a link to click. The Solution on this Talk thread doesn’t mean the problem itself is solved (otherwise the Common Issue topic itself would be marked as solved), it’s just to avoid confusion I’ve seen repeatedly, where people were completely unaware that there is some Common Issue topic linked, with helpful details.
Yes, it’s not ideal, and perhaps confusing for some people. But I see it as a lesser problem of those two, and don’t know of any other better approach to handle it.
Ok, I see now the problem, thanks for answering.