I have not seen it. I'll ping a couple of people and see what we can find out.

It's a little disconcerting and I'm completely stumped.

it's not a known issue  with the IU - confirmed last night.

Most likely, it was a user  and/or SQL issue during the update. It makes schema
changes in the DB, and possible custom code or some other anomaly caused the
issue.

Of course, it might be a 100 other things as well. Assuming you thoroughly
documented the process, I would go back and see every change made (web app,
servers, topology, etc). Did you take the farm offline to do the IU?

Yeah, I took the system completely offline to do this work. Now, would
I be surprised if someone had been in the middle of something when I did
so? Not really...

With the exception of two Bamboo web parts, we pretty much don't have
anything custom going on.