It's not fake; I've seen it in person through an actual running copy of Blockland. Bricks are forced to use the default texture when they are too big because that would mean an increase in the faces exposed. There is no issue with rendering the additional faces. Instead when large amounts of bricks, primarily those with greater surface area, are created at once the client has an issue hiding the additional faces.
What's that called? When an entire brick face is covered so it disappears? That's where the issue lies.
