Hello friends! I also have this problem on my S970. Even if I am careful to lift my hands off the keys, the glitch comes. I also get glitches in MIDI recordings sometimes, even if I don't hear anything wrong while playing. But when I play back the recording, there is the offending glitch. Grrr! Conclusion: The keyboard is not perfect. Neither am I! But, if it is possible to have seamless sound switch, why, oh why didn't Yamaha give it to us! These keyboards are really, really expensive, and many of us use them to earn a living! Another thing; I didn't have this problem so often on my old 2100.