Position Detection during Live Brushing should continue to work as long as your Bluetooth connection is secure.
To brush without the disruptions, make sure your phone is not in “power saving” mode.
If you continue to experience connectivity issues, you may need update to the latest version of the Oral-B app. If, after updating to the latest version, you need to manually re-pair your brush, then follow the instructions “Manually Pairing a brush with the app” under “Follow the steps below to manually to reconnect or add your new Oral-B electric toothbrush to the latest Oral-B app”.