Seems weird nobody else would have noticed this.
I wonder if some other setting is affecting your results on your system.

Can you post a pic of your Options-Prefs-MIDI .. MIDI Output pop up?
Maybe you have some behavior disabled or enabled for MIDI (the Nodes actually use MIDI for the events).

As John mentioned, usually using the 'Render Audio and DXi tracks to stereo file' works exactly as expected (just like the playback in RB).
Using the Save As method, I would actually expect these results, but not using the Render method.

May want to double check that.
Make your sound your own!