Are you using a Bitmain PDU by any chance?

I have had this same issue with several of my T21's (powered from Bitmain 12-way PDU). The issue turned out to be bad connections on the back of the sockets in the PDU, which allows for one phase to drop over time / vibration etc. The miner still powers up but displays the exact same error message you are getting, and finds 0 ASICS in the kernel log - which throws you off the scent, so to speak.

If you power down, pull out the socket that is powering the problematic miner, you will most likely find a loose connection on the back - or pin that is not properly seated in the socket. Or just try swapping sockets / leads over with a different one first.