Mocap Data into Animation Rigging issue

I’ve tried to apply finger mocap data into a humanoid Mixamo character using all the possible variations to my knowledge, that is Override Transforms, Multi-Parent Constrains, even tried to directly assigning coordinates of mocap points’ data into the character’s respective bones.

And in all the scenarios I did get a close result to the desired result, and exactly “the same” result in each case, which was partitally correct, that is except for one thing.

(I’ve used ChainIK between the wrists and the shoulders which does work well.)

In the play mode, the bone renderer behaves correctly - i see the blue skeletons move just as desired - but the mesh components (fingers) deform abnormally, all the finger limbs are twisted. I’ve tried to correct the rotation of the bones to no avail.

I tried to change the fbx to generic in order to be able to use “transform motion to skeleton”, but it’s still inactive.

I tried so many things but couldn’t come up with any good result. Can someone help me? What could be the issue?

Can I extract the bone renderer data into, maybe another character and solve the isssue?. After all, it does behave correctly. If yes, how?

I’m using Unity 2021.3.18f1