I have no clue how this got triggered, I was playing with my friend via Hamachi LAN. We were playing in a SuperFlat world, I dont know wich, my friend made it, It is mainly out of stone, but some dirt and gravel around. We builded things, and then I got kicked out with this error:
Internal Exception: io.netty.handler.codec.DecodeException: java.lang.IndexOutOfBoundsException: readerIndex(16) + length(17573) exceeds writerIndex(16): UnpooledHeapByteBuf(ridx: 16, widx: 16, cap: 16)

This has not occured more than once.

How to reproduce?
1: Create a flat world
2: Connect your friend with Hamachi (different versions?)
3: Build something, and reach some sort of cap.