Async Messaging: customer ends session: how to end agent session?

I have successfully developed a “chat” application using Async Messaging and an intermediary NodeJS service that allows a customer on a website to chat with an agent.

When the customer is done they want to end the session. I call Disconnect Dialog:

https://developers.avayacloud.com/avaya-experience-platform/reference/disconnectproviderdialog

which completes successfully but doesn’t end the agent session in Workspaces (as can be achieved using the chat sdk) – it apparently does nothing.

Is this the intended behavior, or a bug?

If it’s intended – how can I end the agent session?