Connect Chat - 'Not Available' message is not showing even after PRB933587 was fixed in Kingston
Content Management System (CMS)
Fix to PRB933587 was done to the way OOB chat links are configured using "cms_header_chat" UI Macro. This uses window.open() as a customEvent to fire, and when clicking that link, it generates a new window to open. This is done to the .js file in the backend that previously did not work. Customizing this UI Macro to not use window.open() still causes the issue in customers instances.
UI Macro: cms_header_chat
Reverting this "cms_header_chat" UI Macro to OOB resolves the issue.