my 14 yr old icemaker has been making 3-4 hollow cubes per cycle, has been a problem for about 6 months or so (1-2 cubes will be solid & the hollow cubes freeze together in a clump),,,copper water line comes from my basement from a regular hand valve "no saddle valve", & feeds into a plastic line that runs from the bottom back of frig to the water valve in the back top of frig inner. ???
(as far as i know there is no water filter...i have opened & closed the basement handvalve, currently open all the way & when the icemaker calls for water it appears to stay on for 5-7 seconds)