Parkour problems

Put the summary of the bug you're having here
parkour jumping
What I expected to happen was...:
Describe what you thought should happen here
in 0.5.0 when you have four blocks down break the two blocks in the middle. you can jump it but in 0.6.0-0.6.1 if you do the same thing you will turn and fail.It works in both survival and creative
What actually happened was...:
Describe what happened here
parkour became more impossible
Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. first you are in are up high you have a line of 4 blocks a 4X1 rectangle
3. ...then jump you will fail