Have a IS22AGXT000 and ice maker is not operating properly. The front half of cubes are OK but last half are coming out as just a shell of a cube and a frozen clump is forming in bottom of ice cube container. Local handyman came by and said it was filter located in the grill on bottom front. But he had checked everywhere and couldn't find one. This isn't a real old refrigerator and I find that hard to believe. Please advise.