This ONLY affects the SERVER
When executing the command /execute [Player] ~ ~ ~ /playsound minecraft.entity.ghast.hurt 1 [Player]
the connection to the server is lost for the player.
Screenshot: http://prntscr.com/a11chc
The number "1" can be replaced with any number or word
More Info:
Player "A" can "crash" player "B" with this(does NOT only work on yourself)
Related issues
Comments

Confirmed for
16w05b
Seems to be caused by an invalid
source
This can be seen when using the following command with a valid
source
that does not produce this error