I just upgraded to X3 Producer from 8.5 Producer. Transition good. However, when playing back previous files created in 8.5, X3 intermittently ignores sustain pedal data (Control 64) during playback. This results in notes being inappropriately sustained. When I reference the same files in 8.5, I do not have this problem. Is anyone experiencing this, and can someone provide insight regarding this issue?
 
Thanks

Check the "Prepare Using nnn Millisecond Buffers" setting in Preferences > MIDI > Playback and Recording. The current default value  is 250, try 500 (the SONAR 8.5 default value) or 750.

I tried both 500 and 750 without any change. X3 repeatedly ignores the sustain off (0) control at the same points in the file at playback.
 
Thank you. 

Please update to X3D.

First you need to determine whether SONAR is failing to send the message, or the synth is failing to respond. Watch the MIDI activity indicator at the top of the track meter for a flash when passing each pedal up event, assuming you can differentiate controller activity from note ons/offs. If not, you might need to copy the track and thin the notes events so you can see what's going on. Lowering the tempo will also help.  If you see the flash, and the synth doesn't respond, make sure the channel is correct. And what synth/patch is being used?
 
If you don't see the activity indicator flash on a pedal up, that would be really surprising, and I'm not sure what would cause that right offhand. Is there a MIDI FX on the track?

I am appropriate receiving midi sustain on and off messages for the problem track. I cloned the track (piano) and deleted the notes so that I could better observe the sustain pedal midi messages. However, when I played back the cloned track, the problem had been solved somehow. I cloned a another problem track (string pad) and noticed that the sustain problem had been resolved as well. The original tracks were still problematic; however, when I soloed both the problem track and the cloned track, I did not noticed a sustain problem. Can't figure out why this happened, but the cloning workaround appears to resolve the problem. I have quite a few tracks from different files which have the same problem, and I will be applying the same fix. 
 
Thank you all for the help..Peace