
The one on the bottom is the original brush. The one on the top is the static mesh with the overscaled textures. Reading the oldunreal wiki, there isn't anything about texture scaling on the static meshes page.
My process for making static meshes is this:
Intersect brush -> add brush -> align to all around x axis/y axis/floor -> convert to static mesh -> place static mesh
It doesn't seem like I'm doing anything wrong, so why is this happening?