Entity data sometimes doesn't get properly updated in multiplayer

Entity metadata doesn't get properly updated for clients in a multiplayer game in some circumstances due to a networking race condition.

Steps to reproduce

• Start two instances of the game (make sure to use two different usernames, say host and guest)

• Open a LAN server (creative, allow cheats) on a fresh void superflat world

• Place two command block minecarts on connected activator rails (so they activate together)

• Command in one minecart: /tp @p[name=host] ~ ~1 ~

• Command in second minecart: /data modify entity @e[type=pig,limit=1] HasVisualFire set value true

• Spawn a pig near the minecarts: /summon pig ~ ~ ~ {NoAI:1}

• Join the server with the second player (guest)

• Teleport the host far away (200 blocks)

• Activate the minecarts using the guest player

• The pig should appear to be on fire for the host but not the guest

(The order of events is important. To be more precise: the pig needs to be spawned after the minecarts)

Code analysis

The ClientboundSetEntityDataPacket constructor called when an entity comes into a player's view calls clearDirty on the entity's data preventing synchronization with other players.