Possible Fixes

Yes

Modpack Version

10-2.25

What happened?

Steps to reproduce:

1. Join a multiplayer server
2. Disconnect from the server
3. Load a singleplayer world
4. Observe a "connection lost" screen with the error
   
5. Try to join the same singleplayer world again
6. Observe that no error occurs

latest.log

https://gist.github.com/yorkeJohn/60b966f8c05956b6eda5b1f6a3ac788b

Developer reports

No response

I can confirm that I experience this same issue. I want sure whether it's a modpack, some mod, or a Neoforge issue.