If they are sticky and won't remove with policy, two ways...
You can add the Print Server role to the DC and then remove from Print Management.
or
Remove them manually from these keys. (always backup before editing registry)
HKEY_USERS\USERSID\SOFTWARE\Policies\Microsoft\Windows NT\Printers\PushedConnections
HKEY_USERS\USERSID\SOFTWARE\Policies\Microsoft\Windows NT\Printers\PushedPrinterConnectionStore
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Print\Providers\Client Side Rendering Print Provider\Servers\SERVERNAME\Printers
Then restart your print spooler.