Export Humanoid Animation to FBX has wrong head facing direction and twisted fingers.

Hi, I'm not sure what I did wrong here. So basically I've tried to create some humanoid animation clips in UMotion, and noticed the exported result in FBX format has some issues. 

As long as the body and head facing starts to turn to a different direction other than directly aligned with character's Z axis, the exported result in FBX format will have a wrong head facing direction and twisted fingers.

I've tried my own models, the official models from Unity (Ethan and Ellen), and the Robot Kyle model came with UMotion asset. They all have the same issues.

However, when exported into Anim format, the result looks fine. But I don't wanna use Anim format because I'd love to recut the clips in my final project. 

Here are the screen shots of the issue:

1. the original clip in UMotion Clip Editor

2. when exported to anim format, everything looks fine

3. when exported to FBX format, the head is not facing the correct direction

4. and the fingers on right hand looks twisted, they're supposed to held together like a not so tight fist.

So I'm not sure what I did wrong here. Please advice. I did use the original Robot Kelly model came with UMotion. I created IK with direction aligned with character Z axis. I tried with root motion and without it. Nothing works.

Please advice. Thx