LandScape Paint: >3 Materials = Checker map

How come when I paint more than three materials on a block of terrain it turns into a checker pattern?
Is there anyway to solve this?
The first pictures shows three materials being used compared to the four on the outside.

Hi Crofty,

Please have a look at this post for more information:

There is a limit to the amount of textures that a landscape can currently handle. If you are lower than this limit, try painting every layer onto the affected square and see if that removes the checker pattern. If it persists, attempt to paint the entire landscape with each layer (create a large brush and sweep over your landscape with one layer, then the next, etc.). Please let me know if this fixes your checker material error.

I think you’re right. The problem was fixed when I reduced the amount of materials referenced.

My work around was putting the height maps in the alpha channel instead of calling them up. The same applies to roughness.

Cheers.