[Bug report]The "Save Password" pop-up appears again for a site where the password has already been saved.

The site where the issue occurs is here:
https://www.tamakihiroshi.com/premium

This issue occurs only on Safari for iPhone.
(It does not occur with the Firefox extension on PC.)

When logging into this site using saved login credentials via 1Password, I am prompted to save the password as a new entry for some reason.

If I save it at that point, a duplicate login entry is created with a blank username and only the password filled in.

Saving it stops the prompt from appearing temporarily, but if I force-quit Safari and relaunch it, the save prompt reappears.