Does the area turn black only where you are specifically painting visibility? Like precisely on that spot, or does it turn black around that area?
You probably either have a issue with a specific material inside your landscape mat or the visibility setup.
Are you using a modified or custom landscape material? If using a existing material, do you have the hole version also applied to the landscape.
If you are using a custom material you need a hole version, all you need to do to make a hole version is duplicate your mat, and add a “Landscape Visibility Mask” node to your graph, then connect it to the Opacity Mask input of your final material node.
Sorry for the later reply. but hopefully this helps.
