If it is always the same spots that have stubble, then you may want to let it grow for a day or two so that you can see if there is a grain direction change at those spots. Analyze the situation and see if you are just coming at the hairs from the wrong direction.

If it is random places every time then it is technique. I was still spotty with my technique after a year and probably around a year and half before I could consistently get a BBS every day.