I'm not sure if this bug has been addressed for the Java edition yet.
Basically, I had marked a banner on a map and put the map in a chest. When I destroyed said banner, the game crashed. When I re-loaded the world, the banner disappeared entirely, without leaving an item.
Comments 2
Incomplete without a crash report from (minecraft/crash-reports/crash-<DATE>-client.txt). Please attach it to this ticket so that we can diagnose your issue.
Couldn't confirm for MC 1.13-pre4.Cannot reproduce.