When trying to transfer arrows and shulker boxes between my inventory and a chest the item to be transferred will "stick" in wherever it is originally, the inventory or the chest.  Once the glitch occurs I cannot even transfer the items from one inventory slot to another in my on-hand inventory.   It is not a consistent bug and I cannot figure out how to duplicate the bug exactly to give you more info.  Logging out of the realm and back in again clears the glitch.