Hey, I'm sorry if I was too vague.
What I see is that the brush starts to draw "dirty" lines with some pixels on the side, instead drawing single pixels. Like if it was not reset to the original configuration.
Here are the steps to reproduce:
1. open a new document and zoom in
2. draw a curve with minimum brush size (1)
3. increase brush size to the maximum (20)
4. draw another curve
5. decrease brush size to the minimum (1)
6. draw another curve
In my case I see that the line of step 6 is different from step 2. Here is a screen shot of the three curves: