we just observed that even after call has been completed, we killed the agent as well but room is still showing active and running. This is happening after we enabled observability in Livekit.

The dashboard is not realtime so will take some time to be reflected there.

It has been more than 10 mins. Plus duration is increasing even when the actual call duration was hardly 1.5 min. but on livekit the duration is still running and showing 14 mins. How the agent session minute will be calculated in this case?

Agent minutes won't be based on room duration. It will be based on the duration the agent was in the room