Mesh is acting strange in animation sequence

[anonymous_user_41d01051]

I have converted other source to fbx using blender and imported it to UE4

imported data is consisted with Amateur+Mesh in blender

After retargeting every bones, and applied animation

and the result is below.

some parts get abnormally stretched and don`t know why

have checked bone name mapping again, but seems fine

what is the cause of this error and how to fix it?

[event2027]

What happens when you load animation with mesh and skeleton icluded?