Shortcut does not work for OTP autofill

Unfortunately I'm unable to share the specific site but I seem to have figured it out the cause of the specific instance I ran into:

The class list of the HTML element for the username, contained the word "validate". As I progressively removed letters from this word it seems like 1Password checks for the word "date", and the word validate happens to contain the string "date". So Universal Autofill thinks it is a date field and therefore does not fill the username.

However in other browsers like Chrome and Firefox, the browser extension gets triggered when pressing Command-Backslash, bypassing Universal Autofill. Using this method, the problem does not occur. I would expect it to work the same way for Safari.