Hey Gang -- here's a weird niche-case bug I've run into w/ v6.x (currently on 6.0.2 non-Store edition) and the browser extension.
I'm on Windows 7 at work, using Vivaldi 2.2 which I usually operate in incognito mode. When I open a new incognito window and go directly to a login page, the Enpass extension will fill in my login information (using the shortcut key combo), but then the page will refresh with the login fields blank instead of logging in. This happens for any site I've tried it on (e.g. facebook, google, protonmail...). Repeated efforts to log in with the shortcut key produce the same results.
Fun twist: If I go to another page (e.g. my home page) in the new window, then open a new tab and navigate to a login page, the autofill/login works as expected. If I do not go to another page in the new window (i.e. leave it on the Vivaldi startup page) the new tab just refreshes as described above. Also, I do not have this problem on my Windows 10 machine at home (all other details the same).
Have fun figuring this one out!