My rear sun roof don’t open at the first stage with the fron piece but it open in wrong time when the front piece is totally opened as you see in the video attached

 

Our newly acquired 2013 base 2WD Countryman sunroof functioned about like that. My son and I spent about an hour cleaning the tracks with first compressed air, then napkins, then tips to clean out the old grease grime and dirt. Then we applied some submarine periscope grease I had, ran back and forth repeatedly, then cleaned out the tracked with qtips again, and applied the grease again. Works perfectly now.