When I import armature FBX file, Tpose(proper rest position) are gone!

Hey guys! I’m guy using mocap suit, and I would like to record my bone with mocap and import to other blender file.

So I made bone with T pose to mocap.

I finished my mocap with proper T pose as rest pose and tried to export to FBX and re-import to other blender file

But When I imported that bone FBX file, rest position is not a T pose. T pose is just GONE and weird position become a rest position.
I can’t retarget it, I can’t use it and I can’t even use this imported FBX file at all!!!

It keeps happening and I have no idea how to fix it and drives me crazy as hell

I really need help with it.