Hi, A few tips for you:
You may want to look into security filtering on the Group Policy so that it only applies to the Terminal Server computer objects. You can find these settings within GPMC.msc | click on the policy and look on the scope tab.
Or
You can block group policy inheritance on your Terminal Server environment and set up a series of new policies how you like it for the Terminal Servers. Enable Loop Back policy processing so that your user configuration policies still apply. You will need to look into the Merge vs Replace setting for Loop back policy processing (you can use group policy modelling within GPMC.msc to identify what settings get applied on your workstations).
To troubleshoot the workstations that have desktop redirection applied you can run an RSOP.msc or GPResult /Z so that you can see the policies that are getting applied and identify which policy is applying the setting you need to fix.
Regards Big D.