Canvas draw artifacts in Safari for animated, filled Bezier curves

Question

I created an HTML5 animated canvas that uses Bezier curves to draw a filled picture.

I tested it on Chrome for Mac. I just see it on Safari for Mac.

For some reason, I see small figures left by the figures (see below, which moves to the left, and artifacts go to the right).

I start the redraw by changing the width of the canvas to its current width, if that helps ...

Also, if I hover over the canvas or change the windows, the artifacts will disappear. Because I think he decides to redraw it all.

Does anyone know why this is happening?