We have two MX units and two MS switches. The MS switches are connected using LAG, and STP is running in RSTP mode. Each MX has its own unique physical IP addresses plus one VIP (total of three IPs). Since the LAN ports remained active, I now believe that this prevented proper failover behavior. I will run another test by disconnecting the LAN uplink or powering off the primary MX to validate this. Thank you for your helpful guidance. ... View more