Onarock, a couple of things to check for. First check your detergent, if it is a "combination" detergent and rinse additive, or a "tablet or packet" change to a plain powdered or liquid detergent. Most if not all of these "combination" detergents contain rinse agents, and the dispenser adds more agent at the rinse cycle, that can and will cause sudsing. for the time being, make sure the rinse dispenser is set to it's lowest setting(if your machine has an adjustable dispenser). Also check and ensure you're using the proper amount of detergent for the water hardness and soil level.

How often do you need to refill the dispenser ? The rinse dispenser should dispense approximately 1/4 to 1/2 tsp of rinse agent per load, depending on usage, it usually takes a while to empty, If you're refilling the dispenser more than once a month, you may have a "sticky" dispenser valve, and it will need to be replaced.