So if you put a constant effect item inside the corpse of an NPC, if he equips it, then the spell effect animation is played. You can see this if you give Boots of Blinding Speed to Vodonius Nucius, the dead taxman.
In vanilla, this would not happen. But it does make me think - could such a thing have a use, perhaps have a use in scripts? Geteffect from a dead corpse? Should I report this difference between vanilla and OpenMW or let it be?