Public Service Announcement: Do not use a USB C hub to power a Mac M1 laptop. Update Feb 2021: This was fixed in macOS 11.2.2 - ignore this post!
I did this, and it fried my brand new mac. It no longer turns on. Apple has taken the device away to repair.
A google search confirms that many people have the same problem, and the only fix is for Apple to repair the devices.
Check out this forum on MacRumours for more information – there are multiple reports of people experiencing the same problem since. These devices are only a few weeks old - this should not be happening!
Apple guidance is to only power the MacBook with the original charger plugged directly into the MacBook.
When I get my M1 back from Apple I plan to adhere to their advice. Sure it will be a minor inconvenience to plug the original power cable in and a separate USB C hub, but that’s less of an inconvenience than frying my laptop!