CAC 1070 Adapter Audio Problem

Hi,
I received one of your DisplayPort to HDMI 2.0 adapters today. Everything works fine graphics wise with my ASUS Strix Fury except I can not get anything other than stereo in games from my receiver (it is a Pioneer VSX924). When I go to the sound options in windows 10 I can select the output device and choose 5.1 but when I test it I only get stereo sound, the test shows the animation of the speakers in the test but I do not hear anything from the other channels and the receiver displays that it is getting a stereo source.. Thing is if I play a movie and set the player to bitstream just DTS or Dolby I get surround and the receiver shows it is getting DTS or Dolby, but True HD and DTS HD will not work, I find this bizarre to say the least?? Also AMD control centre has a warning saying "your displays do not support audio please choose another audio device from the list"?? I'm running the latest Crimson drivers and the HDMI cable is connected to the same HDMI port on the receiver as it was before and it is a QED high speed cable. I have tried different ports on both the graphics card and the reciever but no matter what I do I can not get even PCM only stereo....Any advice or help would be greatly appreciated!!