GPU Memory Errors at the adapter where the display is connected to

Hi
I noticed that GPU Memory Errors show up only at the GPU were my display is attached to. Sometimes it's hundreds of millions during 24h, yet not causing GPU to hang or cause BSOD. So perhaps I could live with it but I think that long-term it may cause some unnecessary resets.
When I attach display to a different GPU and restart - errors appear at the GPU where I just connected the display, previous one becomes "clean".

All GPUs are XFX RX 480 8GB GTR BLACK, Asus Gaming 5 Z97 mobo, Win 10, Claymore's Zcash 9.2. All cards have the same BIOS and command line parameters when I start the miner.
Note: If intensity or frequency on the display-attached GPU is reduced, there seem to be less errors but still the issue exist. I also positioned the display GPU as the first one in the rack to get the cold air, so it's the coolest one of all (50C).