That happens on my brother's computer, I'll tell him as soon as possible.Generally? A bug in protocol.
Tell him uh,If you can reproduce this issue reliably, helpful information would be your MC version as well as what mods (If any) you're using.
We'd also appreciate if you provide the steps to reproduce this issue and finally video would also be a great help.This message itself is saying the server sent a packet the client didn't know how to read properly.A bug of this nature can be hard to track down, especially if we can't reproduce it.I've noticed you're using 1.9.1. May I recommend trying 1.9.4? It may not make a difference, but it could be worth trying.