Firefox (firefox-bin) 128 crashing on close on some profiles

[Xharlie]

For a while, I have been experiencing extremely frequent crashes with Firefox (concretely: `www-client/firefox-bin-128.7.0-r1` at the time of posting but it has been happening with recent `firefox-bin:esr` version for months, now). I can definitely conclude that 99% of these occur when I close Firefox (possibly even 100%, given some sampling error) and that they do not occur with all my Firefox profiles (I use 11 at the time of writing, isolating use-cases into separate profiles, some of which clear all cookies on close, most of which disallow Javascript except on white-listed sites, etc.)

The observed behaviour is that, with some probability < 100%, all Firefox windows for the profile die when any Firefox window is closed, followed shortly by the appearance of the crash reporter. Restarting Firefox after a crash results in another Firefox window that seems 100% certain to invoke this and also crash on close. Eventually, the state seems to resolve and, for a while, Firefox behaves normally before the crash-on-close bug reappears.

I'm on KDE 6, Wayland, using firefox-bin:esr.

Some interesting things to note include that the crash reporter is actually explicitly *disabled* in Firefox settings and also in `policies.json`:

```json
"browser.crashReports.unsubmittedCheck.autoSubmit2":{"Value":false,"Status":"locked"},
"browser.crashReports.unsubmittedCheck.enabled":{"Value":false,"Status":"locked"},
```

So that should never appear at all, even if Firefox is crashing on close.

Mostly, this is extremely problematic because using multiple browser windows is basically impossible with this bug.

I have tried to isolate the issue and work out some kind of pattern, to no success. I have tried a fresh profile, to no success. As I said, I have 11 profiles. Some seem to remain unaffected but my default profile seems to contract this affliction, again, within some days even if I delete it and recreate it.

I don't even know where to go, next. Obviously, trying to use web search for this kind of thing is useless.

So, I'm asking, here. Does anyone have any insight into *recent* crash-on-close issues with Firefox, specifically on Gentoo / KDE / Wayland / nVidia / more specifics upon request? Any ideas why the crash-reporter is invoked even though I have explicitly disabled it – at least, I think I have? Specific issues related to closing windows when other windows for the same profile are open?