Have you included 'log' statements in your app? If you leave your device connected to B4A and run it in release the log statements will be written out to the log tab in the B4A UI, it is then easy to follow the flow of the app.
If you are using B4A-Bridge and this device runs Android 4.1+ then you will only see log messages in debug mode. This is related to a new security restriction.
Debug mode adds some permissions required for debugging. Maybe one of the permissions is actually required by your app?