I would like to restate my experience in case it can help others.

My G68ADV power supply failed. In retrospect, many of what seemed to be operational glitches as described here had been occurring. When it eventually failed it took out the DAC boards and the tuner module. Changing the PSU alone could not solve the very expensive damage. My dealer suggested that some incipient damage may have been caused before the final melt-down; they could not fix it and the kit had to go back to Meridian.

If you have these apparently benign but annoying symptoms, get your G68 to a dealer for the health check pronto before it goes pear-shaped.

In the spirit of Spinaltap, I would like to confirm that I am not involved in the corrupt theft of a global sport.