DEFINITELY report issues. And no, it's not a demo. Once we've rooted out any issues in this UI, it will become the UI for all users.
HDHomeRun apps are a little different in that we are able to update the UI on the fly, without needing to issue app updates. It's actually part of the point of the new UI. This will allow faster fixes in sometimes near real time with potentially new features at a similar speed. The only time you'd need to update the app itself is for under the hood issues, like video player screwing up in iOS 12.2.