I've got a 3t mutant, and the top cap that it came with sits in the stem more on mine. Yours looks like it sits on top a little bit. Maybe the wrong size top cap? Or is it just not tightened down in the photos?

*edit*- as for the gap in the stem, that not unusual. The Mutant is supposed to be for 25.8mm bars, but I've got 26mm bars in there. People on here recommend beer can shims pretty often (i think the post ^ does this).