I'm really confused now, it just happened on VER15 within 15 minutes... With a different USB drive...
To my knowledge this should not be happening since these are 8GB cards and it will hit 3GB DAG file next year for ETH...
I've had these errors once too, but it was OC. Your temps are nice so that's not the issue. Lower both OC and MC with 100, see if it is stable then. If so, go up with 50, MC first.
I would try Maxximus007's suggestion.
Let me know if you keep getting these errors.
It is also possible that having less free space contributes to these errors with claymore; I think I am going to increase the size of the primary partition to very close to 16gb for the next version for this reason.
Optimally for claymore you should have up to 16gb of free space and use it as virtual memory, I am considering pushing the size to 32gb and implementing this in an alternative build for better ethash mining.