I hadn't noticed that on mine, because it is always to the floor ;D. Seriously, it is kind of twitchy. Some guys are adding a stiffer throttle spring which they claim helps. I have become acustomed to mine, so it does not bother me.
I did this and it completely solved the problem for me.
I made a board cut to the contour of the tunnel and screwed it from below. Then used spray adhesive and some cheap car carpet from Advanced auto and stuck it on the foot rest and the floor where my foot was sliding around. I also put a strip of grip type rubber on the face of the pedal.
My brother bought and installed the heavier spring. I did my fix shown above.
Even with the heavy spring if your foot is no stable and is slipping around then it is a self perpetuating problem when the machine jerks your body and foot jerk and the throttle jerks as a result.
I do not need a heavier spring now that my foot can be planted on a non slip surface and can rest on the side against a higher tunnel just as it does in my car or truck.
Either fix seems to help but even with the jerky throttle as it comes from the factory it is still a million times better then the sore thumb and wrist I used to have every time I spent the day out on the ATV! O0