Your computer waking up from hibernation/standby when turning on a connected receiver is normal behavior - much the same way that turning on any hardware connected to a computer tends to wake-up the host system. You may be able to increase the threshold at which devices influence your systems wake-status by changing your power settings to something like power-saver mode, but I'm not seeing anything for advanced options that would disable peripheral wake commands.
Additionally, the driver does not, nor does Intel provide - tools for monitoring HDMI data transfer or disabling peripherals.
Thanks for your answer, but why doesn't that happen with the old system (PCIe Nvidia graphic card)?
I reinstalled Windows and everything else from scratch this weekend. But, the problem "PC is waking up while turning on the AV-Receiver" is still alive.
On the other hand the problem "Connected AV-Receiver prevent standby" is solved. So, it seems that trying a lot of different versions of Intel 4000 Graphic & HD Audio driver and system settings caused that problem.
I'll test the nvidia Card in the new system (AV-Reciver connected via HDMI to Nvidia card) and let you know the result. So, I'll be able to say if the problem is alive or not using nvidia card.
I'll look also at the HDMI audio problem (see: Intel HD 4000 HDMI Audio Driver issue?) while the AV-receiver is connected to the nvidia card.
I'll post the results ASAP.
I tried a lot of HDMI settings of the TV and AV-receiver yesterday evening.
I connected my LCD TV directly to the PC and enabled the HDMI control functionality. The TV has a menu item "Search for HDMI devices" in order to select a device afterwards to be used with the TV remote.
Interessting and confusing was: The TV doesn't recognize the PC !
After that I changed the connection chain to the original back again PC -> AV-Receiver -> TV
and enabled also the HDMI control functionality of the AV-receiver. Result: Powering off the TV will also power off the receiver imediately, but the PC doesn't go to sleep.
NOW the absolutely unbelievable thing after disabling the HDMI control in the receiver again: The PC stay in sleep mode while turning on the AV-receiver.
I'll check this today again, if the PC will stay in sleep mode, if I turn the receiver on again.
it seems that the error "Power On the AV-receiver will resume PC from Sleep mode" is gone after switching the options HDMI-CEC - or however it is called - on and off a few time in the TV and AV-receiver.
The PC stays now always in sleep mode, even while HDMI-CEC control is turned on in TV and receiver.
So, I can't really say what has caused the change in the behaviour and what was the reason for the PC to wake up, because the Intel driver isn't listed in "powercfg -devicequery wake_armed".
I found this article - An Experience with HDMI Handshake Issues | Missing Remote
Long story short. Connecting your compute stick to an AV reciever just does not work .. I have to switch the power off on the stick and stat itnup. I cannot resume from a long sleep. A short sleep and it all works. If I leave it overnight, it does not wake from slumber. I think my AV is only up to HDMI 1.3