I currently got the intuos art wacom tablet so still learning how to use it. I'm currently in illustrator trying to draw out a map and the brush tool is doing something weird and I cannot figure out why. You can see in my image that where there are curves the black slightly spills over and is filling in half the curve with black. Brush setting is set up as a new calligraphic brush and the size is set to pressure, 3pt-3pt.
I know this post is a little cold but for anyone still running into this issue, set the roundness to 100% under the 'Calligraphic Brush Options' along with your size set with a variable of 'Pressure' (plus a point value for the 'Variation') and you should be good to go! From there you can fine-tune the look of the stroke by adjusting other values such as the 'Angle' option.