Items going from shulker

 The items from my shulker boxes have been disappearing from them. I know that no one has been stealing these items as it is primarily a solo survival world. What has happened is that the first time I broke the shulker and picked it back up and nothing was inside and the second time I picked it up and put it back down and nothing was in it. Please get this fixed as it is very frustrating to lose items that I've spent time getting.