Are you sure it's not because the firmware of the drive spins it down after X period of inactivity?
This might give you some ideas to try: https://unix.stackexchange.com/questions/5211…e-from-sleeping
Thanks for the link I will take a look and give some of the solutions in that thread a go.
It could be firmware, do SSD drives often go to sleep?
Could be a faulty data cable. One or two small thread fractures are enough to have the disk controller or PC go apeshit.
Thanks for the reply, when I swapped to the powered external enclosure its using a different cable, would be surprised if two cables on two relatively new enclosures were having issues but ill see if I have any other cables around to test.