I’ve used my own custom landscape material before, and it did the same thing. I’ve since switched to using the “Landscape pro v2” assets hoping this might solve the issue. Their grass maps are a bit more complicated since it’s all procedural. But even with my own simple landscape material grass maps had reloaded every time even in the packaged project.
Here is the link to the assets I mentioned
Landscape Pro 2.0 Auto-Generated Material
Here is a screenshot of the grass maps nodes.
I super appreciate your help btw 