American Express--autofill fails when username is saved

MacOS, using MS Edge.

Some sites offer to save your login user name; two examples of this are citi.com and americanexpress.com.  In each case, they show those as mostly hidden--for example, johnsmith would show up in the user name field as ********h.  We then need to simply add the password, and log in.

citi.com does this; when I click in the password field and open the 1P browser extension, it lets me choose my citi.com entry and it happily fills that and away I go.

American Express, though, thoroughly confuses the browser extension.  Nothing can happen until and unless I delete the saved user name of ********h and let the browser extension fill in both user and password.

Not the end of the world, just a heads up.  Here's the citi.com login for reference.  A simple click in the password field, the browser extension lights up, and all is well.  Not so for amex.