Not sure if the skulls being outside of the spawn chunks is the exact issue, but when rotating a skull after placing, then leaving the chunks they're in, returning later, they've reverted to the orientation they originally were when first placed instead of staying as you've rotated them. Skulls within spawn chunks don't seem to have this issue, neither do mounts anywhere.
Not sure if the skulls being outside of the spawn chunks is the exact issue, but when rotating a skull after placing, then leaving the chunks they're in, returning later, they've reverted to the orientation they originally were when first placed instead of staying as you've rotated them. Skulls within spawn chunks don't seem to have this issue, neither do mounts anywhere.