Pixelated sprite when changing position

Hi guys, I'm trying to make a porting of my 2D adventure game and I'm using Orthello. I noticed that sometimes my sprites look a bit "pixelated" (a sort of noise) depending on their position.

for bigger sprites the noise is more evident:

it's an OTSprite (named "Cursor") I move following the mouse position, in this way:

 public void SetPosition(Vector2 e) {
   Cursor.position = new Vector2(e.x, e.y);
 }

passing Camera.main.ScreenToWorldPoint(Input.mousePosition) as parameter.

It seems like there are some imaginary lines that make that noise when crossed. Any idea?