Landscape material layer will render in any location other than where I want

I know the material works because it works in other spots.

There are no broken nodes.

I can paint the sand material anywhere except for where I want.

When I paint on the area I want, the texture reverts back to the default checkered texture, and it starts compiling shaders.

It does not revert to the default checkered texture anywhere else and does not need to compile shaders anywhere else.

Only for this handful of landscape squares will it revert, compile shaders, and then never render.

Anyone know what’s going on?

My output log says
LogShaderCompilers: Display: /Engine/Generated/UniformBuffers/Material.ush(35,14-41): err0r X4510: maximum ps_5_0 sampler register index (16) exceeded

EDIT: To be more clear about my issue, the output log does not say the above error when painting in other squares.