Whenever a player gets transferred to another server using Nemisys (The official proxy server for Nukkit), I get this error

16:59:06 [INFO] [LuckPerms] [WARN] User 3ff3f8a6-e264-3586-b633-9a86993bbc45 - funniray doesn't have data pre-loaded. - denying login.
16:59:06 [INFO] funniray[/192.168.254.28:49180] logged out due to [LP] Permissions data could not be loaded. Please try again later.

I'm using LuckPerms v4.0.141 and Nukkit build 145.

Did you try the latest LP build?

Updated to LuckPerms v4.1.82 and same issue

Can you enable debug-logins and try again please :)

https://github.com/lucko/LuckPerms/blob/fef6ebf7930c06add3a17896eee54c7f9070c059/nukkit/src/main/resources/config.yml#L476-L479

The one on the bottom left is the server that is causing issues
It might actually be a Nukkit issue

Seems like the pre-login event is being called after the login event.

Yes, this is definitely a Nukkit/Nemisys issue, you should report it to them.

It was fixed in the latest commit of SynapseAPI, faf298ced5ddb3fa55592a30122c6d62c4969abd