Troubles with vectorial tools

I just installed my Harmony Premium and every time I try to draw with the pencil or brush in a vectorial layer, the line is a little bit “polygonal”, it doesn’t allow me to be precise in details. If I try to repaint the lines with another color, only paints in polygonal shapes, the eraser erases the line in polygonal shapes and I don’t know what’s happening. I fixed a little bit and it seems that the resolution of the visualization is better, but it still making those shapes.