A character, Velma Von Venkman, who I assume is the new Shadow Magic teacher, based on the similarity of the figure of the Arcanum map and the symbol on her clothing, is randomly appearing in Caer Lyon and High Road. She might be appearing elsewhere, but these are the only places I've seen her.
She's a companion you join up with in a quest from Polaris that sends you to Avalon for part of it. She's not a teacher. I have noticed other companions appearing like that in Polaris. Last night I exited a dungeon and there were 2 Baba Yagas standing outside a sigil with no players attached to them. I assume it's the same glitch, companions are being left behind as artifacts from other players being in that area recently.
symbol on her clothing, is randomly appearing in Caer Lyon and High Road. She might be appearing elsewhere, but these are the only places I've seen her.