invalid RADIUS authentication 25.1.5_5 towards Microsoft Network Policy Server

[thorstenR]

We're using the squid module on 25.1.5_5 and require user authentication. An access server of type Radius is configured and this was working properly before upgrading OPNsense somewhere around the April timeframe. The NPS Radius server (Microsoft Network Policy Server) now logs "An Access-Request message was received from RADIUS client x.x.x.x with a Message-Authenticator attribute that is not valid." and therefore all requests are denied. Any idea how to rollback or change otherwise?