Rant - SSLVPN with Duo RADIUS Proxy Change after SFOS 20.0.0

So, I wanted to post a bit of a rant here regarding an undocumented change to RADIUS authentication after SFOS 20.0.0 that has broken my DUO MFA implementation.

For years I have had my users added from AD and I was able to pull multiple groups through this connection.  I use this for many things like differentiating staff and student internet access as well as VPN access to several different systems.  For example one group gives users remote access to file servers so they can access file servers remotely, while another group gives access to a VPN profile that gives them access to our HVAC system (they need this even when on-site).  Authentication happed using RADIUS which went through a DUO proxy server so that they would get a push notification to the DUO client whenever they connected the VPN.  Setup works great.  Duo Proxy was set up to query AD server for username/password verification using AD client and reply back to Sophos using RADIUS with no NPS server involved.

Here is the rant part.  After 20.0.0 my firewall now looks for a filter-id to be included with the radius lookup.  So, now I add the user via AD and I can see all the groups in Authentication->Users on the firewall.  When the use tries to connect to the VPN the firewall wipes those group memberships and looks for Filter-ID to set the group memberships.  Being that I never used filter-id previously it resets the users group to "Open Group" and refuses to allow them to log in.  I opened a ticket with Sophos to get this change rolled back or fixed and they said that I need to set up a NPS server and use that to pass through the filter-id and change my Duo proxy to RADIUS client instead of AD client.  My problem with this is that filter-id only supports one value per network policy.  I am currently using up to 6 different groups per user.  This small change on their system is adding complication to my setup that I did not want to deal with at the moment.