When I visit usbank.com and use Cmd+\ to Autofill the user name and password (or clicking the extension and the AutoFill button), the user name flashes in the field briefly before disappearing, and the password shows up and remains there. Clicking log in then indicates that that both fields need to be entered to log in. Similarly, manually typing in the user name and then autofilling the password causes the password dots to show up, but clicking login produces an error again saying "Enter password to log in". Copying and pasting does work.
1Password Version: 7.6 (70600006) Mac App Store
Extension Version: 7.6
OS Version: OS X 10.15.7
Sync Type: Not Provided