I don’t think it is designed to be in constant contact. I think the idea is to start it, do some adjustments, and either close it or let it disconnect.
I have had somewhat better results trying to start the app again, even though I know it is still loaded. It seems to recognize when it is not connected that way. You should be able to just re-start the app.
It would be nice if it would stay connected, not run down my phone, and act like a remote all day, but it’s not there yet. My guess is none of the brands are there yet.