I tried playing thru a few SMFs with no problem. I checked the manual. I looked for pitch, bend, and shift but found little. Then I checked to see of the pitchbend wheel might be the culprit and, lo and behold, the wheel doesnt work at all!
Now, this is my second 950, so I don't know for sure if it ever worked, but I thought so.
What would cause the pitch bend not to work? Maybe the problem is in this area.
One thing you could do is set the pitch bend value of the live parts to zero in the registrations you use with that midi file. If the problem about the detune is gone then, it could have been both the faulty wheel or still a faulty midi message from the file.