Placeholders in playerheads when using Paper not working
Will be adressed as soon as possible.
BossShopPro sets the owner of the skull to the placerholder when the shop is initially loaded. Paper seems to not allow setting the owner to a placeholder because the placeholder is not a valid player, returning false when the #setOwner method is called. When a player accesses the shop all placeholders are replaced by actual values. Because Paper did not accept changing the skull owner to the placeholder there is nothing to be replaced.
Planned fix: Storing skull owner placeholders in an external structure. When players access a shop the external structure is used to determine whether the owner of a skull should be changed.