Autofill does not count as filled in

I'm trying to use 1Password on the site https://plynniepopolsku.thinkific.com/users/sign_in . If I autofill the credentials it fills in the ID and password with a blue background but when I hit the Sign in button nothing happens. If I type or manually paste into the fields the Sign in button works.

The Create a New Account page has the same problem: https://plynniepopolsku.thinkific.com/users/sign_up

This happens on Chrome, Firefox, and Arc on MacOS. It does not happen with Chrome on Windows.

For testing, you can create a made-up entry in 1Password, as incorrect values should return an error but don't when autofilled.

Versions:
1Password: 8.12.4
Extension: 8.12.2.37
MacOS: 26.3