Miner stopped detecting 1 of 6 GPU's suddenly but GPU is fine.

Im running Asus z270 a pro with 6 EVGA 1070 gpu's on claymore for Etherium and this rig has been running flawlessly for over a year. All of the sudden I was getting errors that one of the gpu's is not working properly. So after narrowing it down to the faulty gpu I unplugged it completely, restarted and miner and it started working perfectly but with just 5 gpu's.

Next I installed the "bad" gpu in a different pc and it worked! I did stress/benchmark tests and it was all working perfectly. I reinstalled the gpu and restarted the miner and got the same errors as before. So I shut down claymore and tried nicehash and again I was getting errors. So then I updated the gpu drivers and swapped everything around like risers, power cables, usb cables, pci slots and it was always the same gpu giving me the error regardless of riser/pci slot/cables variations.

Now I have been running this "bad" gpu in my gaming pc's for over a week and everything is working perfect!!!

Anyone have any ideas??