At my bank web site (https://www.bankofinternet.com/), in addition to the username/password fields there is a search box. When I use "go and fill" my username/password are filled in, but my username also is entered by 1P into the search box, and the "auto submit" is "hitting" submit for the search function rather than the submit button for the username/password. When I look at the webform details in 1P, there are only two entries, one each for the username and password. I tried creating a new 1P login, being sure that only the username/password fields were filled, but the behavior is the same.
Is there something I'm doing wrong here?