Using the following code should prevent an NPC from being able to equip an item, but doesn't seem to work.

set item to GetEquippedObject 0unequipitem item 1

I call something similar to this on an NPC, they unequip the item, then next cell transition they are wearing it again :/ It works fine if I use the no unequip flag when calling equipitem item 1, so this seems really strange. Anyone else run into this issue?

Think this is a documented bug on the wiki, I'm afraid.

I didn't see anything there on its page or in the discussion but I'll take your word for it. Kind of makes me

Might be the GECK wiki then, I'm sure I've seen it somewhere.