Landscape Painting in squares

So my problem is that every time i want to paint a certain area of the landscape it paints in a square and i’ve tried painting all the layers and waiting for it to compile, but it does this everytime. I can’t afford to it on each part of the landscape as I’m using a splat map to do an overall painting and over it i want to put little touches. Any way I could fix this ? I’ve added an image with the matterial and in editor image of how it paints…