Invisible or Missing Chunks on First Login After Starting Minecraft Client (FastLogin + AuthMe + Paper)

[RickPerix]

What happened?

When a player joins the server for the first time after launching the Minecraft client, some chunks around the player appear invisible but there.

This happens to:

• Premium players (auto‑login via FastLogin)
  

• Offline players (no /premium used)
  

Other players do not see the same chunk glitches.
If the affected player disconnects and reconnects without closing the launcher, the issue does not occur again.

This behavior started only after installing FastLogin.

Steps to reproduce

1. Close the Minecraft launcher completely.
   

2. Open the launcher and start Minecraft.
   

3. Join the server (offline mode, FastLogin + AuthMe installed).
   

4. Observe that some chunks around the player are invisible or not rendered correctly.
   

5. Disconnect from the server.
   

6. Rejoin without closing the launcher → the issue does not happen.
   

7. Close the launcher and repeat → the issue happens again.
   

Additional notes:

• Moving away and coming back reloads the chunks correctly.
  

• The issue does not occur when FastLogin is removed.
  

Plugin list

I tested without any plugin except FastLogin and the problem persists.

Configuration file

No changes to the default file.

Server log

No errors.

Plugin version

1.12-SNAPSHOT-65a379c

Platform

Spigot

Relevance

• I tried the latest build
  (build refers to development builds not necessary a release version; i.e. v1.10 is out of date)

• I checked for existing tickets -
  If there are, please vote them with a thumbs reaction and not create new ones