that's not what i see. are you using a drawing tablet?
if so, what do you see when you use a mouse?
Yes. I just tested and it is the same for both mouse and tablet.
I usually use the Intuos tablet.
The Paintbrush doesn't update live, that's why you see those lines; it's not made for sketching, it's for decorated lines, patterns and details.
Ok. I am not using them for sketching,
At least I know that it works that way. It still would be a lot more practical to have a size cursor instaid of a bunch of lines.
It does this only with the Art brush.