massive lag when fireball was spawned

Summoning a fireball (ghasts) at 50 levels create massive lag. The fireball reach a wall, everything drop but wall still there, then explosion occur, my horse died (the explosion was very far away) while the chickens (nearer to explosion) survived???

How to reproduce:

1. type /summon Fireball ~ ~3 ~ {ExplosionPower:50,direction:[0.0,0.0,0.0]}
2. look above you
3. deflect the ball to a mountain/ hill/ anywhere far from you
4. if cannot deflect, use chicken eggs