Move (or copy but then the mover won't move them back, it won't move existing files, you'd need to delete them manually when not needed) using disk paths to avoid issues, e.g. /mnt/disk1/share to /mnt/cache/share, you can also use /mnt/user0/share to /mnt/cache/share, never use /mnt/user/share to /mnt/cache/share.
This, as long as the use cache setting is correctly set.