Thanks for the info:

This is how I created it:
1. Created a song with realtracks for bass and guitar & realdrums track
2. The 3 tracks are highlighted in green
3. Then right-clicked over each track and selected "save as performance file wma/wav"
4. The tracks then are highlighted in orange
5. I see the 3 audio tracks created; mysong bass.wav, mysong drums.wav etc.

So yeah, as Mac says, it seems like the "performance track" (orange) is also playing with another generated realtrack for each track...thats why I disabled the realtrack/realdrums in settings