@audiopacer : I asked an allegedly knowledgeable Accuphase service man in Poland about a USB input glitch in an Accuphase SACD player and he said it's the USB receiver that has been (slightly) damaged most likely due to hot insertion.
Also, I have read that at least the Accuphase DC37's USB input is prone to being damaged by quick power on/off cycling and such. Maybe other Accuphase machines are just as sensitive. Better safe than sorry. More details at the links below:
https://www.snakeoil-os.net/news/computer-audio/problem-with-accuphase-dc-37-usb
https://audiophilestyle.com/forums/topic/29723-accuphase-dc-37-usb-port-problem/

