> But USB-C isn't limited to 5V, power delivery is at 20V. That might explain what's going on here (since the user reports 20V on the output) - it thinks that the peripheral is a power hungry device and it's trying to charge it. That's a problem, but it could be that the peripheral is poorly designed and is mistakenly asking for power that it can't actually handle.

This was my interpretation, the host sets the output voltage to 20V incorrectly (due to a software bug or a hardware failure). Putting a crowbar circuit defensively on the peripheral side would save the peripheral.