I make sure to cycle my ball valves open and closed several times while water or sanitizer is flowoing through them for cleaning. I then leave them half cocked open to hopefully let the cavity dry. We'll see what effect this has whenever I get around to cleaning them.
I did the exact same thing as you, and the result was that the liquid remaining dried, and the ball valves became very difficult to actuate because there was crust right in the middle of the ball. I flush each valve both directions, opening and closing several times, but i leave the valve in the open position when done. Seems to work better.