A VLAN handoff trunks correctly (Auth and Session Failure)

Layer 2 reachability exists and endpoint policy negotiation does not. The service still works through the primary path, but one dependency only fails when the old component is finally drained away. The primary component still serves traffic, yet the retirement exercise exposes a latent dependency on what is being removed. The main path still works until the exercise finally removes the legacy dependency it had quietly relied on.