Trouble with Login: Comcast Digital Voice

Comcast's Digital Voice Login screen has 2 different entry, login fill-ins. There's a radial button selection for the particular login fill-in to be used, and the URL's default selection is the left-side login fill-in. [The 2d login fill-in - on right-side - allows entry of the phone number as the ID.]

I want to use left-side fill-in, which is preselected when arriving at the URL, and uses my ID & PW.

However when Auto Submit is used, 1PW enters the Login ID & PW in both entry fill-ins and then, 1PW auto reselects the 2d - incorrect - fill-in (which was not previously selected). This causes the login to fail since the incorrect ID, for that fill-in, was entered. ...This issue would be resolved if 1PW did not auto fill in & auto reselect the 2d fill-in.

I can work around this issue by changing the Auto Submit to Never, and then, manually reselecting the correct, left-side login and then, manually logging in.

In my 1PW login set-up, for this URL, I have only a singular Login ID and PW entered. And since the left-side fill-in, by default, is pre-selected, I can't figure out how to keep the 2d entry fill-in from filling in.

Here's the Comcast Digital Voice login URL:
https://login.comcast.net/login?s=dvc&r=comcast.net&continue=https://digitalvoice.comcast.net

[BTW, I have screenshot of the Comcast login page, but I can't figure out how to import it into this post.]

Follow-up edit: I've also tested with iOS 1PW 4.1.1, and it does the same thing. Work around allows for correct login.