Linux - mount command returns zero/0 but not working

On a system with systemd, this problem can be encountered when you reformat the partition and try to mount it back.

I moved a disk from encryption to unencrypted, causing systemd’s generated mnt-disk.mount to (where mnt-disk is mount path from /etc/fstab) to refer the old path that didn’t exist any more, causing mount to go haywire.

Just doing systemctl daemon-reload and then doing the mount makes things work.