I've actually had Urianger die in the way wereotter described once. Odd since Alphinaud and Alisaie don't seem to have that same problem with me. As for Dohn Mheg, my NPC team ALWAYS gets hit by the water pillars of the first boss.

Y'shtola gets dunked 3 times. "Not yet . . . Not like this . . ." Alisaie then joins getting dunked. "Don't be so reckless!," says Y'shtola.

The other mechanic they always get hit by are the purple beams from the Ronkan Mage for the Qitana Ravel. They don't even make an attempt at all no matter how close they are to the rock walls. Alphinaud doesn't seem to mind just saying, "Leave the healing to me!"