Break a stroke at the joints
Ordinarily, when you apply a brush stroke to a path, the stroke definition is either stretched or repeated across the length of the path. However, when the path contains one or more corner points (also named discontinuities), you can force the stroke to start and stop at each of these points.
To break a brush stroke at the joints
In the Properties panel, in the Appearance category, under Stroke, select the Break at Joints check box.
To make the stroke extend across the entire path, regardless of corner points, clear the check box.
Note that discontinuities in a path aren't just sharp corner points. In a Bezier path, any corner or cusp node will act as a break point. However, dashed lines are not affected by the Break at Joints check box.