Hollow ice cubes are most often cause by insufficient water supply. Ice makers fill for about 7.5 seconds, resulting in about 4.75 oz. (140 cc) of water into the ice cube mold. If not enough water pressure is available at the fridge, cubes may end up hollow and/or the fill could continue to dribble, eventually causing the fill tube to freeze closed.
If you installed a 'self piercing' saddle valve on your house water pipe, it should be changed to a drill type (which all refrigerator manufacturers recommend). It should also NOT be installed on the underside or a horizontal water pipe as lime and scale, etc., will have a tendency to settle in it eventually reducing flow even more. Only a drill type saddle valve should be used and only be installed on the side or a vertical pipe or the top of a horizontal pipe (if a regular plumbing tap can not be installed). | 
Ice Maker makes hollow ice 
