I have had this happen many times where I am listening to music, multi task to another app on my iPhone then come back to Roon only to find it frozen. Have to force close and re-open to get the now playing status back.
If I choose to go back it does go back but just see an hourglass waiting for a connection.
If this has been reported I apologize. I couldn’t find one. I uninstalled the app and trying fresh install.