Bad Mecanim retargeting results on hands and fingers

I have a Character with a humanoid Rig and retargeted animations from an asset store pack however the hands and fingers are very messed up. I checked the Avatar configuration and everything’s mapped correctly. I even tried retargeting the animation to my character in Maya and it looks fine but as soon as I bring it into Unity the hands and fingers go weird again.

Someone suggested animation curves may fix this. Can anyone elaborate or suggest another fix?

I fixed it by exporting from Maya as .mb (ascii) and in Unity choosing bake animations. It’s better to bake the animations in Unity I guess.