Well, good news / bad news kind of situation:
Good news is I was able to reproduce the problem, meaning it isn't something that is local to your machine.
Further good news is that I see something that is probably related to the problem. In the UV editor:
I recognize this as a bug from older blender versions: Sometimes, vertices got extremely odd internal data, probably due to a memory issue in blender. So it isn't something you've done wrong, it's blender that has played up.
Bad news is I don't have a quick fix for this. It is entirely possible that this particular blend file is corrupt beyond rescue.
You could try to delete and then re-create the vertices that misbehave and see if that helps.
But I'd suggest deleting the misbehaving vertices, export the robe (only the robe) as a wavefront obj file and then start from scratch with a clean blend file where you then import the obj.