I had a combat turn yesterday where it switched to my Paladin's turn (Serenrae), but the portrait did not update. It kept my Wizard's portrait (Maya) for the entire turn, despite showing my paladin's fighting options and information. I couldn't get it to update that turn - tried a bunch of options / inventory open / etc, but the picture didn't refresh.
Not sure how to reproduce this, but figured I'd mention it in case others have seen it. It seems to be rare because it only happened once in my ~10 hour playthrough so far.