The "split" cell sort of suggests (at least design-wise) that a tripple crystal should break up into three singular crystals, and to me it feels more intuitive that way than it splitting into 2 and 1 in arbitrary (though, not random) directions. Also the grid should probably have sides of even length, so that you never wonder which crystal will move first (pic. related), however, not sure how that can be a problem
Overral though, liking the game so far, good luck with the development! <3