I updated both pamac-aur-git and pamac-all-git to 10.1.0beta2 version. For now, tray icon extension is not compatible with Gnome 40.0.
See this commit on development branch: https://gitlab.manjaro.org/applications/pamac/-/commit/93fefcdfedc0ae4b54f95f6b19341d73417f209c
Only pamac development version is compatible. Bug reported here: https://gitlab.manjaro.org/applications/pamac/-/issues/1007
Edit: pamac-aur-git 10.1.0beta2-2, pamac-all-git 10.1.0beta2-2 and pamac-all 10.0.5-3 are patched to work with Gnome 40 until the fix is officially applied.