Cemu

When playing Xenoblade Chronicles X some textures have visible black squares when viewed from a distance (for example the cathedral in the residential district):

The issue is that the mipmaps of these textures are not being loaded (or generated?) correctly. Instead of containing a lower resolution versions of the first mip, they have offset/scrambled parts of the texture.

I also attached 2 examples dumped from Cemu, a color texture and its matching normal texture, both affected by the same issue.

The issue is 100% reproducible regardless of graphics API, settings and graphics packs.
Let me know if you need more information.