Are you using the iOS or Android app?
Because of multitasking limitations on both platforms, there is no guarantee that the app will remain running (and connected to other devices) if you switch to a different app. The app might stay alive in the background while you are viewing a different app, and each platform handles that differently, but as a developer, I have no way to enforce that on either platform.
If you see a crash, please tap Help > Request Tech Support in the app and answer the questions there.