Playing back a certain project, if I start mid-stream at certain points a MIDI track is changing pitch upward by one full step (2 semitones).  If I go further back in the project and start play, then it plays properly. It is only at a few points in the project this occurs.  The notes are mapped out properly -- I've checked them in Event List and Note Properties in PRV.  There are no other notes showing on the midi channel that might be acting as a trigger, other than the desired note.
 
This is a midi channel going to bass synth (Guitar Rig Skobee PreBass), then to my bass instrument track.  Never had this happen, baffled as to what's triggering the pitch change.  I don't think my input keyboard could be affecting this, but the pitch wheel is physically centered; and no controllers are showing for the pitch wheel in this section of the track.

Have you checked the notes in the effected sections?

Just wondering if they have been accidentally transposed when you were doing something else may be...

So you can watch it in piano roll view and see the same note sounding different in certain sections?

Never seen it myself.

Check your Event List for any extraneous CC's

anything like this???  http://www.native-instrum...showthread.php?t=94935

Any pitch markers inserted on the project?

If it's not a Note change it can sound like that if there's a Wheel change event or similar command affecting pitch.  View the event list again and unitick Notes to see if there are any remaining messages of that variety. 

I cannot find anything in the event list that looks inappropriate, nothing outside of the notes being played .  Swamptooth, your link / comment is exactly what I thought at first -- perhaps I had re-tuned the synth so it was modulating upward, but it was still set to standard tune.  The link indicates a problem with playing incorrect notes after modulating to an alternate tuning, which I am not doing -- but I thought perhaps it was a bug in the Native Instruments software.  So I replaced the synth with SI Bass.  At first it played OK, so I thought that solved it.  I reloaded the NI Skarbee bass and verified the same problem.  THen I reloaded the SI Bass, but this time it occurred with SI bass too, so it seems to be something in the midi.

I checked pitch on the keyboard and it seems to be OK, it is what is playing that gets off.

Again, what seems weird -- if I stop the song before vs 2 or the bridge, then resume play from that point, THAT is when it occurs.  If I play from the beginning of the track, it does not change pitch.

Baffled.  And frustrated!

if I stop the song before vs 2 or the bridge, then resume play from that point, THAT is when it occurs.  If I play from the beginning of the track, it does not change pitch.

That suggests that if you find any maverick events, control codes or pitch changes they will be found earlier than when the pitch change occurs i.e. skipping the early part of the file misses a controller that produces the correct pitch.

try running the midi filter on it and stripping everything but notes. insert a second audio track with input from the synth so you can a/b compare them.  then try inserting a whole new instance of the synth with the midi line and a/b that with the original.

does scarbee have an lfo that's going on??  is there an lfo or autowah or psyche delay in your guitar rig setup??? those might be sync'd to cause pitch changes.  

That suggests that if you find any maverick events, control codes or pitch changes they will be found earlier than when the pitch change occurs i.e. skipping the early part of the file misses a controller that produces the correct pitch.

 
IOW, if you stop playback after a pitchbed controller but before a zero controller, then move the Time Line to another location and play, the notes will sound off because they are still affected by the pitchbend controller.
 
To play MIDI notes properly the Time Line has to pass a zero controller first. This resets things to proper pitch.
 
This aggravates me constantly as I'm editing different parts so I find myself placing zero controllers all over the place to fix it.
 
 
PS. Please pay no mind to my post count! It means nothing... HONEST!
 
 
Steve