No Fall Damage Or Jump Potion Effect Equals Massive Jump On A Slime Block

/effect @p 8 10 250 = A Jump Boost That Stops You From Jumping. It Lets you Jump Super High On A Slime Block

What I expected to happen was...:
That I Wouldn't Be Able To Jump At All

What actually happened was...:
I Jumped About 300 Block Into The Air

Steps to Reproduce:
1. Put Down A Slime Block
2. Step On it
3. Do /effect @p 8 10 250
4. Jump