Hi Justin,
In 1.73 I was having problems with held notes in Atmosphere, listed in this thread:
http://www.cockos.com/forum/showthre...3801#post43801
After examining the MIDI file, it turns out that REAPER is recording zero-length notes:
The three notes near the Edit Cursor have zero length when you look at the Note Properties. When I play this section of the MIDI file I get held notes.
The Time Signature for this project is 3/4. Not sure if that has any impact or not.
Cheers,
Malcolm.