Items being deleted from shulker boxes.

I have been in a world exploring end cites for over 20+ hours and sometimes my shulker boxes will lose all it contents. This has happened twice so far and it it quite annoying seeing how my boxes have had diamond gear and elytras. It happens after I put the boxes in a ender chest then after a little time I come back and place it on the ground. When I open it the items don't appear then if I put my cursor on a item slot it will show the name of the item that was once there for a split second then disappear. I have had this happen to two shulker boxes almost full of enchanted diamond gear and enchanted elytras. I know I probably wont get my things back but can you fix it so i do not have to have this happen to me or anyone again because it is quite devastating when i keep my good gear in shulker boxes in my ender chest.