I’ve enabled a trace on your account to help us better understand what’s happening. While the trace is enabled, can you please uninstall and reinstall the app on your phone.
Please note:Pandora Premium and Premium Family listeners may need to re-download some of their offline content after reinstalling the app. Pandora Plus users, however, should receive that offline content again automatically. If you have any trouble with your offline stations after reinstalling, please let us know.
To do that:
Hold down the Pandora icon on your Home screen until all the icons start "shaking."
Then tap the tiny "x" that appears in the upper left of the Pandora icon, and confirm that you want to delete the app.
Then re-install Pandora via the App Store on your device.
Then, log back, reproduce the the stopping and let me know the time and date it happens. I can take a closer look.