Hello,
I have black holes only in the texture. They are on different places, depending on number of faces and depending on texture size and counts. Sometimes it's better to have more texture blocks sometimes it's the opposite.
It's a large model of 500m faces. Decimated to 3.5 million and 1 million faces. And I use 4096 x 32 or 4096 x 16 texture blocks.
There are also some ghost textures.
Kind Regards!