Error when changing backend server

[MotikaCraft-TheJoshua]

Describe the bug Plugin throws error sometimes when player switches server or is sent from 1 backend server to another

To Reproduce Steps to reproduce the behavior:

1. Install protocolize dev build plugin on proxy server
2. Start up proxy server (and backend servers connected too)
3. Join proxy server
4. Send yourself or switch to another backend server via proxy
5. See error happening 1 in 1000 (it's very rare, at least in my case)

Expected behavior Should not happen

LOGS https://mclo.gs/aDqUYEd

Proxy environment FlameCord-2.3.3 & Waterfall for 1.21 Tested with no other plugins

Minecraft versions used If applicable, tell us the used minecraft client AND server versions that are involved in this problem.

• PROXY SERVER: 1.21+ (FlameCord & Waterfall)
• BACKEND SERVER: 1.21.1 (Paper & Purpur)
• CLIENT: 1.19.4