Does this only happen with this particular style and drum kit? Or does the same thing happen when exchanging any sound within a style with another sound? Is it possible that what is happening is actually supposed to happen as a way of auditioning new sounds within a style while the style is playing? Seems like a cool idea to raise the volume a bit in order to better hear the newly selected sound. Then when saving, the new sound is saved at the normal volume level. Have you read through the section of the manual pertaining to changing style sounds? Just a thought. Of course I could be wrong.