Steps to reproduce:
Spectate a player while they eat, game crashes and produces crash report.
MC-86721
Spectating someone while they eat/block with a shield crashes the game.
Resolved
Fixed
1
Resolving as fixed unless people can confirm that this is still an issue. http://hopper.minecraft.net/crashes/minecraft/MCX-2544652/ shows that there are no more reports of the crash since that snapshot.