Upstream has released updates that appears to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing
Bukkit Changes:
b999860d SPIGOT-2304: Add LootGenerateEvent
CraftBukkit Changes:
77fd87e4 SPIGOT-2304: Implement LootGenerateEvent
a1a705ee SPIGOT-5566: Doused campfires & fires should call EntityChangeBlockEvent
41712edd SPIGOT-5707: PersistentDataHolder not Persistent on API dropped Item
If a sync load was triggered, it would process pending join events,
causing them to be added to the world in the middle of the entity ticking
process.
This caused their add to be queued instead of immediate, causing
"Illegal Tracking" errors.
This schedules it to fire at the players next Connection Tick, which
is exactly where this entire process use to run anyways.
Also added missing tab complete and syntax for syncloadinfo debug command