Hi all,
I have a strange problem.
If I import a animation (made with Cinema 4d, Joints, IK, baked to bones and exported as FBX 2010 file) everything is fine.
But if I also animate one angle of the rootjoint, unity goes crazy! Only the rootjoint makes this issue.
In my animation the rootjoint turns arround the y-axis. In Cinema the FBX file works fine. In Unity3D the objekt flips or better it bounces arround the “x” axis!!! After that sometimes the animation hang.
Why?
Is it not allowed to turn the rootjoint/rootbone?
No one else knows this? 
Ok, I still don’t know why unity has a problem with an animated root-joint-angle.
But I have modified my rig, so the root-joint is at another position and has no animationkey, and now it works.