Acquiring missing tracking data using XR Hands

I am using Meta Quest 2 headset to track my hands with XR Hands 1.4.1 package. Is it possible to get indexes of joints that are currently unavailable for tracking (due to covered hands, etc.)?
Documentation in Hand data model section suggests that there exists a method XRHandJoint.TryGetPose() which returns true or false according to if the joint pose was filled out with valid tracking data or not. When I did my testing, it seems that this method never return false, even when I cover up the joints or the whole hand tracking is lost. I would like to detect when any specific joint fails to track due to it being covered (not the whole hand loosing tracking).