Through some limited diagnosis I initially assumed it was the water filter bypass assembly, so I ordered that part and replaced it. When that didn't fix the problem I consulted the Samurai Appliance repair forums, and it was there I learned it was most likely the Secondary Water Valve. Ordered the part from Appliance Parts Pros, received it very quickly, installed it, and refrigerator is now working great. I now only need to return the bypass assembly, but I have no doubt that will be a breeze since Appliance Parts Pros has an awesome 365-day return policy.