I just logged in to test this - 1Password auto-filled in my id/pw *and* then also auto-filled in the 2-factor number. This was so nice! I was immediately taken to my main profile page.
I started using Login.gov months ago (10/23) and recently converted the wife's account as well. Generally smooth sailing for both.
I had the same happen to me when I delayed filing my taxes for 2010 (pure procrastination). I ended up filing 2010 and 2011 at the same time, both mailed in from Mexico. That's when I found out someone else had filed a 2010 return under my SS # from some address in Arizona (where I have never lived). They got a healthy refund from Uncle Sam. It did take me awhile to get it resolved, but I quickly realized that my location and the red tape was going to be a big issue, so I dumped it all in the lap of a Taxpayer Advocate. Highty recommend these people! I finally received my 2010 refund by early 2013 I think. I have also had to receive and use an IRS PIN # each and every year since. Do these ever expire? ¯\_(ツ)_/¯