Gnome-Software does not ask for authentication (and fails to update)

Hi all,

since I updated to 15.2, I can’t update my Flatpak installs. Gnome-Software lists the available updates correctly, but when I hit “update all” (or “update” for an individual one), it will fail to install the update for a lack of authentication. Which is alright, I guess – it should ask for my password, shouldn’t it?
Iirc, usually a gnome-su (or whatever that GUI-Enter-Your-Password screen is called) popped up, and asked me to authenticate. This does no longer happen. It just works for a while (kudos to the devs for not telling me what it actually does) and than fails with a remark on missing authentication …
I’ve tried on both Gnome (default, Wayland) and Gnome on Xorg. No difference here.

Anything I can do about it? It’s probably a bug – can anyone confirm it does not only happen to me?