Are you perhaps using tabs? Dishwashers need detergent in the rinse cycle, otherwise they don't rinse well, and tabs don't let you do that. I've had friends who have always pre-rinsed because of wrong dishwasher use. Once they switched to powder and put some in the rinse cycle their dishes don't need pre-rinsing.
See https://youtu.be/_rBO8neWw04