1st if GPU is OC then revise to default value and run for few hours to check, If still the same problem then change check Sata Cable from PSU is okay not burned etc. then change riser sata cable then usb cable then riser.
Issue will be from above one of them. I believe
I did switch to standard bios on GPUS and i have the same problem.I will change the riser sata cable, i didn't try that yet.Thank you !