XP orbs are attracted to player-disguised entities client-side.

[James103]

To reproduce:

1. Starting with Minecraft 1.16.5, install Fabric loader and Fabric API.
2. Install mobdisguises-1.0.0-fabric and disguiselib-1.0.2-fabric.
3. Create a new world with cheats enabled.
4. /gamemode creative @s (if you are not already in Creative mode)
5. /summon minecraft:spider ~ ~ ~ {CustomName: '""', DisguiseLib: {DisguiseType: "minecraft:player", DisguiseAlive: 1b}, UUID: [I;-1060950283,976832559,-1705744613,865189129]} (summons a Spider disguised as a player)
6. /give @p experience_bottle 64
7. Throw the XP bottles at the disguised spider.
8. Notice that the resulting XP orbs get attracted to the disguised spider client-side, but that they aren't actually moving server-side (causing the rebound).

[samolego]

This sounds similar to predictions of pushing the falling BEs, I could add another condition to if to send more pos packets.