When a partition occurs within site A, resulting in two coordinators in site A (say A1 and A2) and site master in site B notices these two site masters, after the partition is healed, the B master looses route to site A.
1. A1 coordinator of A, A2 common node
2. B1 has route to site A as to node A1
3. A partition split, A2 becomes coordinator
4. B1 notices that A2 joins the site-to-site view and adds another route to site A, overwriting the original route (to A1)
5. A is healed, A2 ceases to be the bridge
6. B1 notices that A2 left the site-to-site view and removes the route to site A
7. There is no route from A to B as the original route was overwritten in 4 and then the record was deleted in 6