There is an issue using hierarchical generation in pcg using the difference node or even spatial nodes. Use the difference node to, for example, remove all grass under a tree or rocks will not continue past the cells/chunks. So it will subtract everything but then once it hits a new cell/chunk it actually does nothing which is to say the least, not very helpful. Anyone found a workaround other than NOT using hierarchical generation for grass? This seems like a pretty big issue for a lot of common gameplay mechanics. Maybe there is another step I need to do in order to get it to continue? Would appreciate feedback before I submit a bug-report. You can see the screenshot below with debug cubes turned on. The same thing works with using spatial nodes.
Reported this as a bug, still no response or acknowledgement on the bug website. Hierarchical generation is pretty much mandatory for any kind of performance around foliage, not sure how this was not picked up during testing.