It happened again and now I'm concerned. About 45 minutes into my set I was playing along with a SMF of Wonderful World using a piano sound on U1 and an accordion patch on U2. Suddenly keyboard went waveringly out of tune, about 2+ semitones. The midi file played in tune while the live keyboard sounds were out of tune. I shut down and restarted as I did the first time this happened, but the board came back up out of tune. I tried reselecting a couple registrations, but no change. I switched sounds and the keyboard sounded normal enough to play using just keyboard, no styles or files - sounded good/normal. But when I switched to the final SMF I realized the keyboard was still out of kilter.

Does anyone have any idea what might be going wrong? I thought there might be some type of trigger in the SMF, but I've used that file forever. Maybe I've inadvertently hit a button, but in the same song - I'm kinda sure it was the same song. I haven't done any real troubleshooting because I don't know what I'm looking for. HELP!