Just installed and tested 21354.
This version does fix the problem of WinTV not working correctly (no live tv, can't find any channels, can't find tv tuner) that began in 20H1.HOWEVER, 21354 DOES NOT fix the problem of the live TV STUTTERING that has been present since 2004.
Continued here: 21354 - Hauppauge WinTV v8 software not working correctly with HVR-950 - Microsoft Community
Have you try HVR 950 WinTV 10 ? as WinTV 8 is no longer supported.
Live TV Stuttering can because by a lot things most common cause is USB speed or Video driver some time out date app software and with to many other device on same port that sharing across with other USB device and but my guest is your Surface Pro 4 has some kind of incompatibility with newer OS or WinTV 8 it self that has incompatibility give NextPVR, SichboPVR a try on newer OS.