Ahh the good old cable defect. USB and even SATA cables die on me all the time.
Depending on the way audio gets transferred using USB it is possible to avoid that. I believe RME USB3 interfaces use a different transfer modus.
Audio would not be degraded but simply would not arrive if the error correction/detection gets overwhelmed.
Anyway thanks for reporting the solution, the USB cable is often overlooked when it comes to audio degradation.