What, if any, MIDI data is being sent if you just start the MIDI monitor and play nothing on the keyboard?
If I hit "Record MIDI" this is what shows on the MIDI Monitor (see attached image) with those last 3 entries being generated by the count-off on the drum track. So it looks like Source "1" is the BIAB program itself. These entries are before a single note is played on the MIDI keyboard.