The first Feral Halflings conversation (the one with Entu) causes the second group of Halflings (in the furnace room) to turn hostile to one of their own members: As soon as your conversation with Entu is finished, the two Halfling Warriors attack and kill Necre.
While testing, I found a similar quirk of their AI: If you Ctrl-J directly into the furnace room (or, I imagine, sneak past the first group of Halflings so that Entu cannot initiate conversation), Taibela has a pacifism problem: She will cast PfMW as soon as she sees you, and then do precisely nothing for four rounds. She does not, however, suffer from this problem if Necre has already been killed. Quite curious.