Ray cast cannot shot target if scaling triangle mesh shape in a non-uniform way

[ChivenZhang]

I just use btBVHTriangleMeshShape for a human model. I want to implement the actor picking in my editor, when I scale the model in one axis, the ray cast seems to failed, i cannot get the expected rigidbody in the raycast result callback. I am confused whether i used in a wrong way because it works fine to raycast the primary shape, like box or sphere shape.