I think this could related to auto-filling password? I get the endless spinner when using Bitwarden auto fill (Firefox on iOS)
my workaround: auto fill your username and password, touch Login, type an extra letter in the password field after your password, delete that extra letter, touch Return again.
Seems like I'm not the only one being confused about this: https://mastodon.social/@mcc/110526680864188856
People are copy-pasting a post URL in the search box and sometimes it works and sometimes it doesn't.