Mainstage 3 Randomly Transposing

The software is randomly transposing +/- 1.5 semitones while playing. I am using an M Audio Keystation 49 ES through a USB port. The sample rate of all devices is 44.1hz. The bug appears randomly after using the software for some time. Each time I choose a new patch or hit MIDI reset, the bug is corrected, but almost immediately returns for the duration of the session. Shutting down Mainstage and the computer does not remedy the problem. This makes Mainstage completely unreliable for use in live performances.