Connection Lost. Internal Exception: Packet 66 was larger than I expcted

Get the following connection lost text:

internal exception: io.netty.handler.codec.DecoderException:java.io.IOException: Packet 0/66 was larger than I expected, found 3 bytes extra whilst reading packet 66

This happens every time a skeleton fires an arrow at me. Also happens sometimes when attacking spider with sword.

Also, the latest enchanting/repairing changes are brilliant. The game has never been more fun!