Ground texture broken after enabling dbuffer

I was having issues with decals, getting them to render properly, but I finally got it with guidance from here:
https://forums.unrealengine.com/development-discussion/rendering/71315-opaque-decals

It seemed to work fine until I went to the Venus level, and this happened to my textures around my volcano! Any suggestions on how to fix it? I have re-built the level, tried to retexture it (textures don’t appear to change the checkered area), change the terrain slightly to force it to recompute, and none of that has worked so far… Any help would be greatly appreciated! At first, I thought maybe the moving lava texture was messed up somehow, but it looks fine in the pyramid (where it is a ground texture). The checkered part is the part that broke, and I am trying to fix.

I finally figured out with some experimentation that the lava texture doesn’t work anymore within a “block” with the rock texture. It did work okay with lava / dirt. Not sure why still, but I was able to work around it by making the volcano out of dirt It would be nice still to know what is going on here.