It is simpler than that…… each and every sound the phone makes, even keyboard clicks is streamed to the HAs. so the HAs immediately turn on streaming mode. When the stream finishes it reverts to Autosense and not you previous program unfortunately. Most people turn off all but essential sounds that the phone makes…. Clicks, notifications and so on.
This is apparently going to be fixed (we hope) n the next version of the app, which is long overdue.