Freezing water line?

Our Hotpoint side-by-side refrigerator's (HSM25GFRE SA) water dispenser freezes regularly. In the two years we have had it, it freezes sooner and sooner. After turning off the freezer for about 4 hours, the water works and it has always produced ice cubes.

I disconnected the water line at the blue connector just below the freezer door and it pumps great. I did some searching online; what I read was a poor design causes this problem and this model has a sealed door - no chance to open or service it.