SlimeSquared

The game doesn't crash, just logs the exception. I'm not sure if it interferes with the packet being handled, but I assumed that any thrown exception is probably something to be avoided if possible.

So, you joined a LAN server, and went through a portal to the same dimension as the host, and it still didn't throw? I'll try it on another computer.

Strange. I can try to see if there is some other condition that causes the exception. In my testing, it was when there was a player (in this case, always the host of the LAN server) on the receiving side of the client's dimension switch. I'm not sure exactly how this situation changes the packet sending on the client.

https://github.com/SlimeSquared/DebuggingMod I forgot to mention, I did my testing on a LAN server, if that affects anything.

I'm using 1.18.2, forge version 40.1.0. I have encountered this IndexOutOfBoundsException when sending packets to the client at the wrong time (during a dimension switch, when dead, or on login). If anyone has any insight, I'd love to hear it. Here's the example mod created to replicate the error (using the PlayerChangedDimensionEvent): The client log: The server log: