Bungeecord-related.

Problem

Sample setup:

Server A:

• default server for bungeecord
• teleports player to spawn on join
• redirects with PluginMessage immediate to Server B if Server B is empty

Server B:

• teleports player on join somewhere

With some lag from the player, the teleport accept of the teleport of server A (id 1) gets sent to server B who also sent a teleport to the player with id 1 already, as id 1 is the starting id.

This can cause an anticheat to falsely think a player accepted a teleport and then see the player potentially hundrets of blocks away from its original location.

Suggested solution

Randomize starting teleport id.

Alternative solution

Let bungeecord handle teleportation and teleport accept packets to shift ids.

Although this might solve this problem with bungee for non-spigot servers as well

• most are using spigot
• the problem does not appear often as the setup is not common
• the fix in spigot is much easier and requires less resources.
• a clash of randomization ids is so uncommon that ignoring it should not cause problems