I rode 100 miles today with the quickshifter turned off. The bike did not stall at all, and the bike shifted much better when using the clutch with the quickshifter off than it does with the quick shifter on. I will ride it a few more times before my 600 service next week. But it sure looks like the stalling is tied to the quickshifter. If so, could be linkage adjustment or ECU fix. I’m encouraged!