I have a banking website that has something similar. The site has 4 fields:
Country (Drop Down - Automatically populated)
Organisation ID
User ID
Password
Enpass does not fill in anything for this site. I even tried deleting the login and entering the password, but Enpass doesn't even seem to pick up that the login needs to be saved. 1password was working for everything except the Organisation ID which I would have to copy/paste in manually.