Detecting dead nodes

I got a dead node - the door sensor is not responding (dead batteries? not sure yet), but it is not visible on the dashboard nor in the device list, that its no longer functional. So it was always showing armed and not tripped AND (!) in good state - i.e. green configuration “gear” icon. From time to time Vera tries to poll it and fails - i.e. red “pencil” icon, but it disappears in several seconds, while green “gear” icon stays. Which is misleading.

Should Vera automatically detect dead nodes when it fails to poll it for a number of times?