It might not be, but it takes 15 seconds to rule out… I’ve seen similar things happen on flat surfaces, but it depends on how subdivided the mesh is and how the vertex normals are on it (smoothing groups and such).
It’s hard to tell with the single picture though. It could be a compression issue, but that would be some pretty extreme compression. DXT uses what, 4x4 blocks for compression? That would mean the lid has a really tiny resolution, but that can’t really be the case because if you look at the trim and text resolution, there is plenty of detail to them. Unless the normal map is at a much smaller resolution than the texture map.
Can you post your UVs of it? One of the islands might be too small or something. EDIT: Oh and one more thing, where did the texture come from? Was it originally a jpg or something? The only way I could see blocking like that happening would be if it came from a jpg because they use much larger chunks(8x8 or 16x16, don’t remember off the top of my head).