The only way for that to happen is if they previewed a reply/new thread screen and then not actually follow through with posting. I do see one post for them but like you could not find it. This preview bug is an old one and I am not sure it is something easily fixed. But that is the only way this could happen other then having myself or BbBoy manually adding
the username to the memberlist which we will do upon an admin's request. Usually when someone deleted a mod/admin without removing their powers first and their name still shows in the In Power screen. I checked all your settings so this is the only thing I can think of that could be how this happened Lehcar1477.