from what i've heard (i don't have the game on 360), pretty much all items are getting added effects. to me, this sounds like the old problem where when i introduced personal items by actually equipping them to characters, i saw "bonuses" to other equipment.
and since each save can have separate add-on powers, i'm thinking there is something in the save pointing at relative positions in the items.engb file (highly theoretical, i don't know this stuff really) AND keeping information about items within the save, so it might pick up another power if the file changes and something was inserted somewhere in the middle.
