that is exactly what happens when a mod try to alter thralls (add emotes or other functions to the thrall) and the mod is removed. the thrall init logic which runs whenever the server starts and queries the existing thralls from the game.db breaks when the mod is removed. this will also remove all thrall related data (name, tier, faction, …) from the game.db and results in default values and all the thralls are nameless performers without an owner.