I've noticed this minor issue for a long time. Fill is flaky in the discussion forum at
A couple of ways to get login to work:
1) Press CMD+\ twice. The first time, the user name fills. The second time, I get the expected asterisks in the password field, then can press CR to log in.
2) Press CMD+\, then press CR, sometimes once, but often more than once. The password field never visibly fills, but eventually you do get logged in.
Bottom line is it ultimately works, but not in the elegant way we've come to expect . I consider this a low priority annoyance.
1Password Version: 7.5
Extension Version: Not Provided
OS Version: macOS 10.14.6
Sync Type: 1Password