Just did an ET run earlier today and whenever somebody casted Praefatio, it was acting funny. At first I thought just I wasn't getting the skill icon, but still had it. So then I walked into a monster and it hit me for damage, and no Kyrie Eleison animation showed at all. However, whenever I casted single target KE, it worked fine on me. Not sure what caused it to go crazy. I also had Assumptio, and casted Praefatio, and it I didn't get the barrier AND I still had the assumptio on.
I'm unsure of what would have caused that, and it's pretty annoying.