Your Team-Up Unavailable due to Enemy Team-Up?

Not sure if this has always been like this or is recent, or if it is even a bug (seems like it might be, though).

The locked Team-Ups for a match included not just the expected 6 characters (my team and the enemy team), but it also locked Iron Man team-ups, presumably because the enemy Team-Up was of Iron Man. This happened on a Deadpool Daily Quest node, where I only noticed it due to trying to delete a Ballistic Salvo I accidentally accepted.

Screenshots below:

This is normal behavior for PvE nodes, as far as I know.

Enemy team-ups are treated as being on the enemy team for the purposes of character selection in PVE. The only exception is for survival-type nodes, where you don’t know the enemy’s team-up ahead of time.