I've just run a Medium Game, and found there were two solutions to the puzzle. The game is 45828 with the following grid
453798216
879126534
126354798
931562847
768941325
542873961
6*5637*82
384215679
2*7689*53
The first missing numbers are 1 or 9, 2nd = 1 or 4, 3rd = 1 or 9 and 4th = 1 or 4
Could this be normal, as I though the system generated only games which had only one solution ??