[Bullet] Unable to use imported collision data in other nodes

[nellodotca]

Godot version

3.3.2.stable

System information

5.12.12-arch1-1

Issue description

It seems you are unable to use the collision shape data imported from blender in other collision shapes. I'm using the "-colonly" hint in blender which, when imported into Godot, results in a scene with the following nodes and resources:

Spatial -> StaticBody -> CollisionShape.shape(ConcavePolygonShape)

I'm trying to use that ConcavePolygonShape resource in this

Area -> CollisionShape.shape(ConcavePolygonShape)

It doesn't matter if I duplicate the ConcavePolygonShape, duplicate the CollisionShape or even ConcavePolygonShape.set_faces(ConcavePolygonShape.get_faces()). Nothing I do will let me use the imported shape in an Area -> CollisionShape. That same data can be used in a MeshInstance.mesh(ArrayMesh) just fine.

Steps to reproduce

Attached is a reproduction project. The left cube is an Area Mesh with CollisionShape.shape(BoxShape) that was created in Godot. The right cube is an Area Mesh with a CollisionShape and the shape is set in Spatial.gd. The third cube is a MeshInstance.mesh(ArrayMesh) that was created using the imported shape data.
You can move the cylinder left and right with A/D or the arrow keys. When the cylinder collides with a cube it should print "entered" in Output. This only happens with the left cube, which is the problem.

Minimal reproduction project

test.zip

[pouleyKetchoupp]

Confirmed in 3.4.beta5, when setting concave shape faces by script, the internal shape doesn't get properly updated in Bullet.

Note: Doesn't occur when switching the 3D physics engine to Godot Physics.