I have an ongoing issue with audio / video outputs from a pc I have in my living room.
Itís an i5 with 16GB ram running win10 pro. The machine has 2 1660 graphics cards in it (used for folding when not in use for other things) and itís generally used for playing video and audio to the surround sound receiver (Denon AVR2000) and tv.
For clarity there is also a Focusrite external sound card setup with a mic and separate headphone output which I use for video calls but this isnít causing a problem and isnít used here (and indeed this problem exists without this attached and/or installed).

I run 2 outputs from 1 of the graphics cards, a DVI and a HDMI, into 2 separate inputs on the AVR unit. One is used as a video screen for playback and one is used as more of a system screen, I rarely need to display the latter as I VNC into it on my phone to control the video output.

My problem comes after a shut down / restart / sleep and wake of the computer. On a couple of occasions it switches on and whilst the screens are located in the right place (video on the left) , theyíve swapped physical outputs, and thus inputs to the AVR. The main problem is that MOST times it switches the audio around. And the audio is coming from somewhere I canít find. There are 6 Ďinstancesí of NVIDIA output in the sound control panel (6 video output). The two that are plugged in are the only 2 enabled ones, but sometimes another one appears to be plugged in, so I have to enable that one and disable the other. I often have to disable them all. Restart and then enable them to get any sound at all. Itís as if itís trying to be too clever and automatically set things up, but it doesnít know what Iím trying to achieve and Iíd really rather just manually control things, the comparison I can make I guess is like a static IP address.
Sorry itís wordy, I suppose my questions are, Is This a common issue? is there a way to manually assign a gpu output and itís associated audio output to just stay as it is and not try to Ďknow bestí. After a restart itís really pot luck whether Iíll get audio or have to unplug hdmi cables. Restart the system. Plug them in then rename the outputs again.

I hope my issue is understandable and there may be someone who can help.