It didn't happen on the idle_shake animation?

Huh, what the heck is happening on my pc?

Edit:
Ok, tried messing around in the .qc
And removing some other sequences, it seemed to have fixed it?
I'll have to do more digging in this.

Final Edit:
Ok found the problem.
This is more of a compile problem where I put some animation with an extremely high location value (to make a certain part "disappear".
The moment I reduced the location on that part, the shakkyness is fixed.

Thank you xdshot for your help in me debugging my problem.
Sorry if I wasted your time.

The specific bone isn't parented to anything and it's using Quaternion.

Tried removing the rotation and the problem still presist

So, It seems like I'm the only one that's having this problem, but it seems like the position of the bone in animation isn't being exported at the right position.
While the misalignment is very small, this create some shaky animation where my gun is moving around the hands.

Strangely this only happened on a single .blend file that I have.
https://pasteall.org/blend/a4e8f8cedc774df29d445093eedcd23a

Anybody else have this kind of problem?

Update:
Found the problem
This is more of a compile problem where I put some animation with an extremely high location value (to make a certain part "disappear".
The moment I reduced the location on that part, the shakkyness is fixed.

Blender version: 2.92
Source Tools version: 3.1.1