I will do more research, but it appears that all my item frames are gone. here are two screen shots of 1.14.3pre2 (with frames) and 1.14.3pre3 with them gone   Edit: I loaded a backup I had from 1.14.3pre2 that had the item frames (the one pictured below) and then loaded it in pre3 without moving, and checked several places I had item frames (on different kinds of blocks) and, yep. Pre3 destroys them. I thought maybe they were just invisible, but, no, they are gone. *EDIT #2:* Placing Item frames seems to crash the game as well.