Druid Spiritshift Party AI Bugged?

So I've gotten back into Pillars for a second playthrough with the release of WMII and I haven't played since the game's release. The new Party AI system is great for the most part but when it came to trying to get Hiravius working the spirit shift AI option didn't seem to cause him to actually do any automatic spirit shifting as the option implied. Is there some trick to making this work or is it just bugged?