If you run iostat and see this error message against the eUSB device (Product: eUSB DISK) , and there are no outstanding related FMA faults, you can safely ignore this message.
# iostat -En
c2t0d0 Soft Errors: 0 Hard Errors:0 Transport Errors: 0
Vendor: MICRON Product: eUSB DISK Revision: 1111 Serial No:
Size: 2.03GB <2030043136 bytes>
Media Error: 0 Device Not Ready: 0 No Device: 0 Recoverable: 0
Illegal Request: 39 Predictive Failure Analysis: 0
This is a spurious error that does not impact the functionality of the system.