landscape with 4k-8k highmaps, the layers are not painted

Hello, is that right?

When creating landscape with 4k or 8k highmaps, the layers are not painted. The surfaces are grayed out and remain gray! At 2K Highmaps everything works fine. Is there a limit size in the Unreal Engine at Landscapes? It would be bad if you want to create an Open World Map, but because of a bug, you can not create big maps.