Comment # 26 on bug 1174939 from Wenruo Qu

Also surprisingly, even with that 5.8.0-default kernel compiled from commit
9bc0044f23a1ebc1496c9ed8967e0aa5d0a5685e, the kernel mount the dumpped fs
without any problem, and qgroup rescan also works perfectly.

This means the on-disk data of the fs is completely fine.

So it must be some runtime problem.

I guess a reboot, and then try "btrfs quota enable" still doesn't work right?
BTW, could it be related to btrfs-progs? What's the version of btrfs-progs?