Being asked for WiFi password which is already known

Every now and then I am asked to enter the WiFi password. The password is already known and already prefilled in the popup - I only have to press enter. But - why is that?

The popup steals the focus and if I am typing without watching the screen I mess up the password by adding whatever I was typing to the WiFi password, having to reenter the correct one a moment later.

My laptop is switching between two APs in the house often. This sudden Wifi-Key asking is starting to drive me mad, though. I cannot predict when it will ask me, sometimes it does not happen for a day, sometimes a few times in an hour or so.

I am usually able to solve most issues myself, but here I don’t know how to get rid of that. Any idea how I can begin troubleshooting this?

(Manjaro stable, XFCE.)

Edit:
CPU: i7 mobile
Kernel: 5.5 and 5.8
Wireless card: Intel Wireless 8265 / 8275 driver: iwlwifi