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)
Mine does that when my water pressure drops too low. I’m on a well so my water pressure is low to start out with. If my sediment filter fills up, one way I find out about it is hollow cubes. You may want to put a pressure gauge on your water feed line to verify enough pressure is coming through (maybe you have a restriction somewhere).