What the title says. I'm playing PotD so I don't have a save just before that fight but it's pretty easy to recreate. It seems to happen almost all the time, just make sure you affect enemies at the same too. It didn't work when I tried to cast it only on top of my party.
OK, my bad. Ignore this thread for now or delete it as I don't see a way to do it. I didn't notice my character had been confused. However this has happened to me against creatures that can't confuse,charm or dominate. I don't have a screenshot though. I'll try to recreate it properly and get back here.