Landscape Height Blend Questions

So I’m trying to follow along with this tutorial: Landscape Material Tutorial Part 1 (Unreal Engine 4)

I’ve followed it as closely as I can without having the exact textures that the author has (They were apparently custom made for this tutorial and are not available otherwise), and I’ve run into a problem at the very end. I can paint my dirt and mud layers onto the landscape, but I only see one at a time. With the dirt layer as the base, I should expect to see parts of it peeking through when I apply the mud layer. Instead the mud layer covers it entirely, which leads me to believe the height map portion of this isn’t working.

Here is everything I have so far: Game Dev Height Maps

Let me know if I need to get any other images to shed light on this issue!