Mecanim humanoid rotation offset issue

Hey,

I am working on a controller for a humanoid character using a custom rigged character. The skeleton has a root node at the origin of the scene rather than at the hips. Most of the animations seem to work just fine by checking "Baked Into Pose" and using "Original" as what the root is based upon. I'm running into problems with this one animation where the character is knocked down and the entire body lies flat along the ground. Mecanim seems to be applying some kind of orientation change because the character is rotated slightly so their upper body penetrates the ground and the feet are slightly raised. I have tried importing the asset as a "Generic" rig as well and this fixes the problem. I would like to be able to use the Humanoid rig though because it would allow retargeting. I have attached a screenshot of the problem as well as my animation settings. If anybody has any advice it would be greatly appreciated.

Thanks!

EDIT: It looks like the animation is being adjusted based on the avatar's muscle setup. Not sure how I forgot about that! I guess you can't expect to have a 100% accurate animation when using the humanoid system, although it's pretty close.

 

Just want to let you know that years later, I stumbled upon the same issue. How could I forget about muscle setup??
So thanks for taking the time to write the solution you found!