I was exploring the end with my stepson (both on Win 10). We were in an end city after raiding it and placed our Ender Chest to secure all of the loot we just acquired. I removed a shulker Box from the Ender Chest, placed it down and opened it, dumped my inventory, and the game crashed as I was placing the last items.

Upon re-launching the game, the shulker box and Ender Chest were both missing from my inventory and weren't present in the End City (we spawned in at the exact location we were at during the crash). Between the Shulker Box and Ender Chest, most of the items we needed to successfully explore and return from The end were missing, along with several of my best enchanted diamond weapons, armors, and tools (which were in the Shulker Box). Although an enchanted diamond pickaxe and set of boots that I just acquired, and hadn't yet placed in my shulker box, were still in my inventory.

After some understandably nervous deliberation, we decided to continue exploring The End since we had three End Cities within render distance, two with ships, and we came there for Backup Elytras. I was also concerned that I had lost my other items, including our enchanted Elytras, that were in the now missing Ender Chest. Once we got the the second floor of the next End City, to our surprise, there was an Ender Chest in the same general location that ours went missing from in the last End City. Luckily, all of my original items were present, besides my Shulker Box with all of my loot and equipment. To be clear, this was absolutely a different End city, one with a Ship, where the one the game crashed at had no ship. 

We moved on to the next end city, and there was yet another ender chest in a similar location. Very strange. 

This is something I would greatly appreciate someone looking into. Had I placed more, or more irreplaceable, items in that Shulker box, this crash and subsequent loss of all of its contents very likely would have ended my positive experience with this otherwise excellent and wonderful game. Having to fear unfairly losing the items that I've spent so much time and effort getting, is the difference between me continuing playing this game and recommending it to everyone, and me giving up on the game entirely. I don't have much free time, but I spend most of it playing with my stepson. So losing so much progress is a big hit to me. I understand how much work goes into this game and how difficult it is to find and fix these issues. But this is an unacceptable and game-breaking bug. 

Side-note; I previously had another Shulker box end up missing, but thought I simply misplaced it or accidentally dropped it. But I'm starting to think that it actually went missing due to this bug, as I have no idea where or how it could have went missing otherwise. 

Thank you for your time and consideration! Truly!