WebXRManager: Decompose cameraVR.matrixWorld (#21964)

* Core: Robustness.

* WebXRManager: Decompose cameraVR.matrixWorld

src/renderers/webxr/WebXRManager.js

@@ -378,11 +378,15 @@ class WebXRManager extends EventDispatcher {
 
 			}
 
-			// update camera and its children
+			cameraVR.matrixWorld.decompose( cameraVR.position, cameraVR.quaternion, cameraVR.scale );
 
-			camera.matrixWorld.copy( cameraVR.matrixWorld );
+			// update user camera and its children
+
+			camera.position.copy( cameraVR.position );
+			camera.quaternion.copy( cameraVR.quaternion );
+			camera.scale.copy( cameraVR.scale );
 			camera.matrix.copy( cameraVR.matrix );
-			camera.matrix.decompose( camera.position, camera.quaternion, camera.scale );
+			camera.matrixWorld.copy( cameraVR.matrixWorld );
 
 			const children = camera.children;