Theme issue with Firefox Snap update to revision 3068

[Colin Law]

On Mon, 4 Sept 2023 at 16:59, Little Girl <littlergirl at gmail.com> wrote:
>
> If I log onto the machine as a different user, I no longer have the
> issue and everything is working as expected, even when switching to a
> dark theme.
>

That suggests it is your profile that is causing the problem.
Possibly the update adjusted the profile in order to be compatible
with some new feature, and didn't make a very good job of it.
Unfortunately I don't know any way to recover from that other than to
create a new profile, in which case you will lose any personalisations
you have made (I think).  I don't know whether you will lose all your
passwords, open tabs etc.  Hopefully others will know more than me.

Colin L