Coming from physics, any change you make in a turn other than an increase in the throttle, will change your acceleration and thus affect the turn. if you are leaned over a lot and depending on how much change you make, it could cause problems.

I'm no racer, but I tend to either keep it in first until I get mostly out of the turn or quickly shift to second before I start my lean.

but then again I'm riding a bike with a claimed 54hp. so most likely your bike is more powerful than mine and a slight change in your throttle will causeca bigeger power jump than mine.

there's the old saying that "slow is smooth, and smooth is fast". I find that when I focus on my technique, turns are a lot smoother.