1) Delete all agents
2) Setup autoregistration with single action - add host
3) setup agent 1 and agent2 (go) on the same host - both with the same configs but different hostnames (Hostname1, Hostname2).
Of course they should not be able to run together at the same time - since they would block the socket
4) Run agent 1 - let it autoregister, - create any item there, close it down
5) Run agent2 (go) - let it autoregister, create any item there, close it down
6) Now - both agents should have the same red interface availability:

7) If you start any single agent now (but not the other) - the interface availability on both of them will become green

It is definitely wrong to update the interface availability in this case on the agent to "Availabile" - considering it has always been down.