It’s due to the geometry. The bush has way more detailed geometry than your meshes (probably) which allows it to more accurately be lit up by the lighting. See here, particularly the vertex normals bit Foliage - polycount
It’s due to the geometry. The bush has way more detailed geometry than your meshes (probably) which allows it to more accurately be lit up by the lighting. See here, particularly the vertex normals bit Foliage - polycount