User duplicates being created constantly, not being read from AD.

Hi there,

I have just stumbled up on an issue - on our XG a handful of users (not all) are being created as what looks like "local" users on the XG.
Normally users are STAS'd and compared to their AD account and registered with their "account@account.com.au" username but these others are being listed as just "account" as their username.

It appears the users can still surf (I have set up temp rules to apply to the Open Group) but these users shouldn't exist.

If I delete the users, they pop back up after a little while (Haven't confirmed yet, but assume the user on the other end is dropping session and signing back into the captive portal, or possibly being STAS'd again)

See below for example accounts. 
Top 2 are how all accounts are formatted, the bottom account is one in question which is causing problems.

I have double checked all the OU's that are syncing and confirm there is nothing astray.
It appears to be a handful of users that exist is multiple OU's on our AD. Can also confirm that their original account that has synced from AD when we first implemented the XG is present but for some reason when they start a session it is defaulting to this weird empty account.

Any thoughts would be appreciated.