Could be far off the mark but I tend to have similar problems with "over shaving". If I actually let stubble grow, the shave is comfortable damn near every time. If I shave every day or twice a day WTG, I'm fine. Its when I start doing back to back ATG shaves that I start getting minor issues. Its usually minor minor ingrowns under my chin (probably because my angle is wrong) but sometimes I get minor razor burn.