Page doesn't stay fixed on mobiles

I'm not quite sure what the correct terminology is, but when viewing on a mobile, the page seems to wander a bit horizontally. I notice it happens on the parallax Frame demo so t isn't something I'm doing wrong. It is a bit disconcerting if you scroll up or down it will sometimes not center itself, leaving a slight margin on the right. Otherwise very very nice them and will probably buy it if this can be fixed.