ich have two pairs of 4500X-32, with other word two vss-systems in a test environment. IOS running version is 03.05.02.E.152-1.E2, dual-active detection with a fast-hello link is running. When i pull the VSL connectors to simulate a failure the active switch go into recovery-mode. After the vsl is restored the switch in recovery-mode start a reboot as desired. The configuration is saved and if i repeat the procedure, all is working fine. But when i start the systems the next day and begin to test the dual-active detection again, the vsl port stucks in " waiting to be aggregated" after restoring it. No reboot happens, the only solution is to reboot the switch manually. After that this misbehavior is repeating. Only setting the dual-active detection interfaces to its default, and reconfiguring them for fast-hello dual active detection again brings the feature back to normal operation:
switchport mode access
Both vss systems shows the same behavior from time to time, i have no explanation, can somebody help?