Ok, here is the video:
I have enpass open on my external display (WQHD resolution).
You can see me clicking on the enpass icon, then it flashes up and is gone, another click on the icon does nothing (it is open in the background)
If I click on the browser (or somewhere else) it closes in the background hidden and I can click the icon again and you can see it flashing.
After I clicked enpass icon, I can type my password (hidden) and then you can see it open with a very big font).
I hope this clarifies what is happening
My setup has one Laptop (4k) and 2 display (WQHD)
When I move the browser to the laptop screen, enpass opens without issues. When I move the browser back on the display it will continue to work until I lock my screen. Then it is broken again.