In Ethel's hidden room (where the masks are lying) - we snuck in, and then when I dropped sneak she appeared, but didn't talk to me. She was just frozen there, unmoving. We did the whole dungeon, then came back, and fought her - she seemed to take extra damage and would only run around, not attack. Got some extra XP when she died.

I've summoned an imp for Wyll, and when we go to camp for the end of the day it's frozen next to him, just hanging in space.