I have not heard of any such thing occurring on its own. If you have a GoPro or cell phone camera, set it up and observe yourself playing. How would you describe your playing on a scale of 1 to 10, where 1 is relaxed to 10 being extremely energetic?

I've had it happen to me twice while playing live, out of about 10 live performances and 20 or so rehearsals since I got the board late spring this year? Never happened in a rehearsal or while just practicing at home.

First time i didn't realize it had happened but for about a minute while playing a song my playing sounded "off" and didn't know why. I couldn't figure out why i was off, at the end of the song I noticed the transpose button was lit. I guessed maybe i accidentally pressed the button, though I didn't think I had. Then the second time it went "off" during a performance I quickly looked at and noticed the transpose button was lit so i pressed transpose down to deactivate it. This time more sure I didn't accidentally hit it

Both times it shifted up an octave, not sure if that was your experience (always "up"?). both times I was playing a bit aggressive but not pounding out notes. Scale of 1-10, i'll give it a 6 - 7 in vigor. Its never happened while just practicing at home, no go pro evidence to share sorry. but it did happen. twice.

(add): Mine is a MOXF6, not 8

I still recommend a cellphone camera, GoPro, or just a fellow musician watch you as you play - just to eliminate any possibility that it's not your energetic approach to attacking the keyboard.
Second recommendation: place a matchstick or small piece of paper on top of the button and see if you wind up knocking it on the floor during play.

Third recommendation, take the unit to an authorized service center... explain your issue. They will probably clean the electronics, and maybe charge you for labor (their time). If it is really a problem, the cleaning will probably fix it.

thanks Phil. its not a big enough deal to disrupt my busy life. i'll keep watching for it. I am sure i didn't hit the transpose button after the second occurrence. its really not in a spot i'd accidentally hit, i'm not using other knobs or buttons around it while playing, i have a latching foot switch to activate AF1, which is the only thing I use up in there. I pre-program everything and dont' use transpose, note shift or any of those buttons live. Twice in 30+ live band events isn't enough issue to drive me 50 miles to the only authorized service guy I know of in San Diego and leave it for 2 weeks. its not often enough to even hope to capture on video - i'd have some fool standing there for hours hoping to catch lightning in a bottle and odds are he/she'd get nothing but bored. i'm in monitoring mode now, it didn't happen the last 2 gigs and I have another 6-7 months on the 1 yr warranty.

a matchbook won't work, it won't stay there long. I had my guitarist arrange a bunch of her picks on the top left corner of my keyboard at our last gig. they were all on the floor within 3 songs. I can't really change my energy level for this issue either, I rock out at a 7 and its part of the overall act that we all pretend to rock out, I'm slowing down from my younger days when I could take it to 11 🙂

I know I probably sound crazy, but so glad to know it's happened to someone else! I'm so worried it will happen while I am performing somewhere.

I've actually had another musician watch it happen to me while playing -- twice.

I was playing pretty soft right now (maybe at a 4-5), and it just happened again. I might look into my warranty or look up an authorized service place. Didn't think about that as an option. Thanks!