[MC-73312] Tall stacks of mobs will fall apart

If you create a stack of around 20 or more mobs riding each other, the stack will start falling apart into separate stacks. You can replicate with this command:
/summon Spider ~ ~1 ~ {Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1,Riding:{id:Spider,Invulnerable:1}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}