I've noticed a texturing artifact after adding a few textures to the terrain in the World Editor, which can be seen in the attached screenshot. This seems to happen when I try to blend a few textures together on the terrain. Is there a multi-texturing limit on the terrain?

Hi,
There's max of 3 materials per triangle and around 256 per single area.

OK, that explains it. Don't remember reading that anywhere in the documentation. You might want to add a note in the documentation about that.