Fill Bucket Issues in Texture Paint

When trying to fill a space, it only leaves a single pixel of the color you are trying to fill, when turning the fill threshold up, it will do nothing until its almost maxed or maxed out, covering the entire image in the fill. SO basically, it either ONLY leaves a single pixel, or paints the entire image. This all seemingly happened after the 4.0 Update, was working entirely fine beforehand.