Animation is not exporting as it is suppose to work after export

Hi there!
I am using a Mixamo character in blender. I used the Mixamo control Rig plugin. I then mixxed mixamo animations with custom animations. This is to be used in Unity With the Humanoid set up.
The character in Unity is a CC3 generated character.

My issue is that even though the animation in blender works and looks as intended, during the export, the fbx skeleton is wrong and the animation(s) is distorted in unity. To double check in case i used wrong settings in unity i loaded the fbx file also in an empty blender and the problem was still there. Basicaly the problem is on the fingers and legs.

Do i do something wrong in export settings?

Any help will be appreciated.

Mh I am not 100%
but try disabling “Only Deform Bones” in the export settings. Sometimes excluding bones in a full hirachy can lead to problems

Thanks for your reply @PolyPigeon

We tried what you suggested however there was no better result.

here is an other example of the issue that we encountered

The avatars are in T-pose. The characters are the same however we use the humanoid set up, as we need this specific set up in out project.
We encounter issues such as these with any type of animations (Rokoko MC, Mixamo MC, Handkey animation, with rigify or directly on a game rig without controllers correcting animations with animation layers).

Also other problems are the sliding feet. Even on standing idles where there is no movement / animation on the feet at all. In some cases the Final IK unity plugin helps.

Just want to make sure the issue is blender origin or unity origin.