thanks for that, I have played around and found out that the problem is slightly different... the shortcut for autofill is to blame, not the Browser
there seems to be an issue with the Apple (in my case MacBook Pro, macOS Big Sur Version 11.5.2) keyboard and Enpass, I had to test several different shortcuts to eventually find one that works,
it is (for me) a very awkward one and I would prefer using something else, but some keys are just not accepted in some browser, f.e. the key '#', why is that???