Because it’s 2023 and we can’t get basic UI that works properly?
Maybe this is the relevant line of the crash log: Object Gio.DBusProxy (0x55e4d0f30a90), has been already deallocated
I think this is true, since I get Gnome crashes in the bluetooth settings and nowhere else.
The real annoyance, though, is that pressing cancel/off does absolutely nothing if the microwave is being used as a timer (without the microwave itself running). When the timer beeps, my first thought is to press cancel/off. Then press it again a few times, because it's still beeping. Then I remember that there's a dedicated button (somewhere in the middle of the panel, labeled with small text) to cancel the timer.