I'm not sure...but this may tie into what you are seeing. To first clarify, I had no effects or filtering engaged, but just the other day I noticed similar wave shape peculiarities on the oscilloscope. What I noticed (and I don't recall off hand which oscillator it was) but if I'd pan left or right, then one channel was mostly triangle while the other channel was more sine. In otherwords, the wave shapes seem to vary slightly contingent between left and right blend. Not sure, maybe it's designed that way. All I know is that after not touching this instrument for a month, and then hearing it again. Wow, it sounds so darn good.