Adding new components to a Landscape breaks Landmass

I found another person asking the same question, sadly with no answers. Adding new components to a Landscape makes it unable to be affected by Landmass. Any existing Landmass would be flattened, and new Landmasses don’t affect the Landscape at all. Does anyone here know a fix to it?

With World Partition, it seems to me the only way to expand a Landscape is to add new components to it. There is no way to connect a new landscape to an old one without using World Composition if I’m not mistaken. If that’s the case, then it’s likely that you would want to expand a Landscape with new components, but that renders Landmass useless.