Quick recreation of this scene including skills, vassalship, pact, imps, did not induce the smiting for me.
If the very foundations of morality and alignment are involved, I should mention here another oddity from this week: Shortly after Vanis the Hun descended into pariah-hood, my mortal (
clash.php?op=character&id=105548 ) who was on the scene got their name in the healing menu dropdown. I was unable to actually heal, but injured demons should not appear there. This shaky partial demonhood seems related to Bapt's experience.