DIAGNOSIS: The freezing cycle is getting interrupted, so the ice isn't forming completely. This is almost always a temperature problem.
FIX: Check the ambient temperature around the unit. This machine needs to be in a room that's between 50°F and 90°F. If it's in a garage, shed, or next to a hot appliance like an oven, move it to a cooler, stable spot. Also, make sure there's at least 5 inches of clearance on all sides, especially the back, for proper airflow.
IF THAT DIDN'T WORK: The issue could be internal. The evaporator might be freezing over. Unplug it, let it thaw completely for 24 hours, then run a clean cycle with a 50/50 mix of white vinegar and water to clear any mineral buildup affecting the cooling system.
HEADS UP: Don't just add more water thinking it'll help. An overfilled reservoir can actually contribute to the slush problem by lowering the overall temperature in the ice-making chamber.