LIVE: Character is jittering with Blend-Weights enabled

When changing the value of the blendweights of a character in a level, it is breaking the animation that the character has and causign the animation to show as jittery.

1) Download the .rar file attached to this post.
2) Extract the file to your Unreal Projects location in Windows Explorer
3) Open the changelist version of UE4.
4) Create a copy of the file after double clicking to open the project
5) Once the project opens, Locate the Blueprints folder in the content browser
6) Drag 'Balltest' and 'BallTest2' into the level.
7) Hit simulate under the play options
8) Look at the 2 Character in the level

4.5 preview breaks rag doll / animation blendweight