Firefox themes not working

Hi community,
I’ve switched to manjaro gnome a few days ago (so far so good) except for firefox themes.
I use Firefix 99.0.1 (64 bits) gnome 41.5
Manjaro Linux ; (identifiant de construction : rolling).
And when i try to select an other theme than default, the default minimize, full screen and close buttons turns into dots, and the theme doesn’t work.

Is that a known issue ? do you guys have any clue on how to deal with it ?
Thanks in advance !

Any updates on this?