If you still have enough water in the bottom of the unit that you can see it, that would explain the dishes still being wet. The Dryer comes on, and once it gets hot, begins to create steam that keeps everything wet. It's possible that the anti-backflow valve is stuck open and allowing water that's still in the drain hose to flow back into the dishwasher once it's done its complete cycle. The valve has a soft rubber flap inside that, depending on age, make, and composition of it, may be a bit warped or deteriorated, or my be stuck open due to a piece of debris being stuck in it. This would be the first thing I would check since you say that the dishes are clean but still damp. Also, as others have mentioned, if the disposal (if you have one) has debris stuck in it, water can collect there and flow backwards into the machine. When we still had a disposal (removed it because disposals are no good for septic systems) I always tried to make sure to run it while wash water was draining from the dishwasher. That helps to keep the disposal clean and clear and draining properly, and keeps the lateral line from the disposal to the drain clear also. Incidentally, another good way to clean out a disposal is to use ice cubes. just remove the black rubber guard from the sink drain, fill the disposal with lots of is turn on the water and then the disposal and let it run till the ice is all gone. It's amazing just how much crud can build up in a disposal, which also causes odors after a time also. Plus, the ice helps to keep the grinder blades sharp.