MIDI pitch shifts unexpectedly in PT8?

[NS3474]

Hi guys and gals,

I'm running PTLE8 with an Mbox. I am using XPand2 for a bass part, and my MIDI keeps going from being in tune to about a 1/4 step SHARP. No pitch bending, transposing, or anything else going on. This is happening seemingly without cause (i.e. I play 6 or 8 bars with the correct tuning, and then it instantly switches to the sharp tuning, never at one particular spot). Anyone have any idea what's going on? I tried closing the session, closing PT, and restarting the computer. Each time the MIDI returns to pitch . . . for a little while.

Thanks!