I use fullscreen apps all the time and I noticed after the last couple of 1PX beta builds, my Mac app popup (1P mini) that comes up when I unlock 1PX via desktop integration seems to change positions each time. It never docks at the top of my screen from the 1Password for Mac icon in the menu bar. Instead, it is constantly shifting to a new position on screen.
Two examples of subsequent unlocks:
Note: I am using Brave but I recall the same thing occurring when using Chrome.
1Password Version: 1Password 7 Version 7.3.BETA-10 (70300010) AgileBi
Extension Version: 1.15.8
OS Version: 10.14.4
Sync Type: 1Password