OK, this is a strange one. I must be missing something.
I have 3 routers in a lab connected to the same switch with the ethernet interfaces for all 3 routers in the same vlan on the switch -- vlan 2.
I placed all 3 routers in an HSRP group, with R! as active and R2 as standby and R3 with a priority lower than R2. No biggie -- textbook set up.
I cant get the environment to stabilize. R3, with the most inferior priority, keeps declaring itself the active router and R2 and R1 do receive that hello from R3. R1 and R2 respond with Coup messages declaring that R1 is active and R2 is standby. This goes on for ever. Then R2 gets into the act and declares itself Active.
Most bizarre are the interface resets on R2. They keep incrementing until I shut down R3s ethernet interface....???? When I shut down R3's interface, all goes normal, the environment stabilizes, the elections for active router end, no more weird stuff occurs, and R2s interface reset stop incrementing completely.
Take note that it did stabilize for a few hours and then I shut down R3's interface and brought it back up, and now it hasnt stopped with this cycle of events.
Please see attached router config and log info.
PS the switch is configured with each switchport facing the routers in vlan 2 and no errors on the interfaes.