Have you tried another gpu in the motherboard that's stopping to mining? It might be that the graphic card is overclock? If you are using msi afterburner or other pls uninstall or reset and try again, memory overclocking can cause this problem too
I unfortunately dont have another GPU to test with on that board, my 3070 is part of another build. I had an overclock on before (50 on core and 400 on memory) that I removed and put all back to stock including power back to 100. That has made no difference.