WebXR - Child (2D) camera keeps looking at the initial target while parent rotates

Questions
1

There is an object3D parent-child chain hierarchy.
I’m using .setRotationFromQuaternion() to rotate 2Dcamera’s parent according to XR camera.
A mesh is also child of the same parent.
While the parent rotates, the child-mesh rotates too, that is, it updates both its position and orientation, but the child-camera while updates its position, it does NOT update its orientation, so it keeps looking at the initial target based on its direction when WebXR session started (no target was specified)!

This didn’t work:

camera.updateMatrix();
camera.updateMatrixWorld(true);
camera.updateProjectionMatrix();

How can I made the child-camera …stop staring at that point and update its orientation too?

2

I just found out that this problem is caused by the fact that the child camera is a depth camera, so before the main rendering the renderer uses a depth material and a depth render target for depth rendering.
Then the material and the target are changed for the needs of the main rendering.

This setup works perfectly in 2D, and in custom 3D VR code, and this issue is caused ONLY in WebXR mode -a very “touchy-feelly” black-box API with lots of issues and inconsistencies…

Any ideas?