Posted this elsewhere, posting here too in case it helps someone else.
Happened to me. Also, fsdBeta bricked my AP with 10.4 download on 11/7/21. Mobile service replaced the USB hub, it failed again the very next drive cycle (said there was nothing they could do for the AP since it was on Beta). Multiple updates later; no software fix. Got it into the SC; motherboard not talking to the daughter board — new MCU. Tesla said the three are not related (USB malfunctions, fsdBeta/AP malfunction, MCU malfunction) but that replacing the MCU fixed all three (which sounds like they’re all the same issue to me…).