I operate a 4100D Groundsmaster and I notice that alot. When I am mowing the big field near a helipad, I mow North/South. The next time the big field is mowed it will be mowed east and west. I don't know why the discharge chute is angled towards the main wheels/tires. Stains the wheels. When there's dew on the grass it collects on the front tires. Gotta have traction. I never mow when it is actually raining. I may have to leave when it starts raining. A light mist is nothing.