In my Realm, updated to 1.14, items in item frames disappear. Everything else spawns in normally, but any item frames and the items they contain disappear. This has happened twice, and not every time, but a lot has been lost. It may be a chunk loading issue, but maps, weapons, blocks - anything in the frame is gone, and not dropped.

This happened in 1.14 and 1.14.1 (after release, no snapshots.)