After struggling to survive the Dragon, because of other bugs, I built a stair case leading up to a crystal. Near the top, I died. When i returned, I picked up my items and continued building. Upon reaching the top, I broke through the iron bars, and hit the crystal, which killed me, as I knew it would. However, when I returned to the End, the crystal had returned, the iron bars had returned, and my stair case had been deleted, along with all of my items that I dropped when I died. Everything gone, and blocks had disappeared.