Troubleshooting Blend Shape Transformation

I have a human character that I need to transform into a beast during a run animation. I set up the mesh to have a blend shape (aka morph target). Standing still it performs correctly, the verts and bones all move to the desired position:



But when I try to do this during an animation, things go bad:



I've tried everything I can think of and I can't figure out what's going on with the hands and forearms. Still screenshot:



And screenshot of meshes and bones in 3ds Max:



To be clear, this is only one asset in Unity. A mesh of a man with a skeleton and a single run cycle, and that mesh has one blendshape. I think that bones might be inheriting the scaling of their parents, but I can't find any way in Unity to restrict bones to local scaling only.

Any ideas on what might be happening here?

 

What kind of rig are you using for the character, Humanoid or Generic? I think the issue might be arising if you are using a Humanoid rig on this. Generic rig is friendlier to the manipulation of bones than a Humanoid rig. Generic rigs are friendlier to the manipulation of bones than a Humanoid rig will ever be. This is because the Humanoid rig is going to convert bone transform movements into muscle space and from what I understand it doesn't easily allow for scaling bones. Also, you might want to take your question over to the Animation forum. Hope that helps you out.

Cheers,
TrickyHandz