Bukkit

Components which are most provably envolved:

- Spigot 1.10.2
- AuthmeReloaded
- Multiworld

The issue:

EnderPearl clipping was long ago erradicated from Minecraft Vanilla, however, there where still some issues where AuthmeReloaded would incorrectly attribute a player's Y axis position on logout. This issue by Authme was also corrected recently, but it seems Multiworld still somehow causes this.

I've done extensive testing, and I have come to the conclusion that this only happens if Multiworld is applied. Does Multiworld manage player coordinates or safely place them on login? Because that could be the issue.