Thank you! I just bought myself a new amp (Denon AVR-X3500H) and a new graphics card (Asus GeForce GT1030) an had exactly the same issue (HTPC is connected through the amp). Installing your build fixed it . Now need to work on getting the Astra and SES UHD Demo channels to play smoothly...
I've been distracted with real life since I started this thread.
A couple of months ago I installed a Nvidia Gforce GT 710 replacing the old Intel on-board graphics card. This made no difference to the issue, but after AberDino's success with the latest build I decided to give it another go.
Good news is suspend and TV power off are now resuming correctly for me also with Sebastiii's latest version. I'll be looking forward to the final 1.21 release to see if this issue is now a non-event for me.