I've got the same issue like you, i was fighting PP 25 hc, I died & released, & i get wow error & 8 items were gone + spec bugged. i made a ticket & GM reply, they can't do anything, i can't believe that GM can't do anything for helping us, aren't we a community? its not our fault if we get wow error, we didn't delete our items & we call for reimburse.
Now, do i expect another wow error & more items will lost? If yes, will you fix it? If you don't do anything about that it's better to leave the game, before i get a heart attack or something like that.