I have experienced a similar but slightly different issue. The Username and password are filled in, but unlike the mac version it does not complete the log in but at that point I have to click on the web site login button.
I just split your post from the other thread since it is a completely different issue.
Autosubmit is not yet implemented on iOS, but it is on our list. I'll make sure the developers get your vote for it. For now you do need to manually submit the form in 1Password's built-in browser on iOS.
Please let me know if there is anything else I can help with.