I've seen this issue happen with Unity(longstanding issue), but I guess I've never actually tried it in UE4 before now. I'm using a custom DAZ transformed character, for the record. Whenever I manipulate the morphs for the mouth inside the UE4 editor (4.21), the teeth do not follow the mouth and instead stay in one position. It's a little disconcerting and looks horrible. Is there any fix for this? Other than creating a custom morph slider inside of CC3 and playing with the settings until it works? It works the way it's intended inside of Character Creator, but once I'm in UE4, the teeth don't seem to respond to anything, and there's no morph slider for them.