Broken landscape blending

Hi, I have a landscape material applied to the entire landscape actor, but in four specific sections of the landscape, material blending isn’t working correctly — it just shows a strange texture.


I know this kind of issue can happen when trying to blend three materials, but in this case, there’s no third material involved. Even after deleting and re-adding those sections, the issue still appears.

You can see in the bottom-left corner how the material is supposed to look.