1Password cannot autofill Google credentials

honumael

So that means it's completely out of 1Password's hand, right?

Essentially so, yes. Password AutoFill, which is part of iOS, is the thing that's detecting and filling forms and 1Password can offer to pass on the relevant information, but only when (and if!) Password AutoFill asks for it. As in, if Password AutoFill never asks 1Password for your email address, it can't be autofilled.

We have found that Safari can handle these two-page sign-in forms better than third-party browsers – even when you're not using the 1Password Safari extension – which suggests that Safari may have something of a "home advantage" on iOS that other browsers don't get.

The text replacement method that Kester suggested is probably about as close as you'll get to a workaround unless that changes, but as you mentioned, Masked Email addresses make this a bit more of a chore. In that case, you'll probably have to Copy and fill passwords into apps that don't work with 1Password.

I hope that explains things fully, but please do let me know if I can be of any further help. :)