We have a DMVPN set with two main routers, we have our primary head router and a backup. One of our spokes keeps losing connection to out primary router, the second tunnel to the back up is up and works. The issue we are now having, is when tunnel one goes down and anyone from our core tries to go to this stub, one of the other stubs says they know how to get there and not our dr head router.
The two head routers are connected by a point to point tunnel. The head routers and spokes are connected by mGRE