Your app is not running twice.
Your Samsung device doesn't "behave" as it should be. Starting from Android 4.1 it is not possible to read the logs of other apps. So B4A-Bridge should only see its own logs. To workaround this issue other B4A apps, in debug mode only, send their logs to B4A-Bridge over a UDP connection.
The expected result is that you will see the log messages once. On some devices the new Android 4.1 limitation was not implemented correctly and the result is that you see the messages twice.