The Dwarfs I was farming seemed to be on a similar timer as by the time the last one was dead a few more had respawned. I've read on other forums that lots of packs of mobs have been set to have the instant respawns in old world content like in pandaria. I'd hope they see false positives are impacting legit customers and put in a fix for it like you mentioned. However since this apparently something new people don't know much about, it does concern me knowing there is an invisible limit that can trigger on you.