I will be doing my scales and will be fine for a while, then I start to mess up. I stop and do a different guitar practice method. Once I am finished with that method, I go back and do the scales again, this time I seem to be doing them better and at a faster pace. Does switching tasks, clear my mind so that I am more relaxed? Or does muscle memory gradually get better?
Generally over 9 repeats of a given task tends to render it pointless. So upto 9, then switch, have a break, clear your mind, you will progress a bit quicker.