I just bought a brand new MBP 14" M3 Pro and I have the same problem. Mine occurs when I try to charge via usb-c hub and put my MBP in clamshell. The first time it happened, my laptop was just 3 days old. I brought it to the service center and they couldn't find any reaosn for the error. All ports (usb-c and magsafe) refused to charge even with their cables and adapters. So, they replaced the unit. Now, three days form when I got the replacement, I tried to do the same thing again (charging via usb c hub + clamshell) and it stopped charging again! This is exhausting. Apple, please fix this!