You will have to rebuild your landscape and likely physical material between edits.
When I was using physics-masks inside PCG, this seemed to be a regular thing I would have to do to make sure any updates on the landscape took, else I saw what you are seeing that ALL the points come back as a single physics-type.
I’ve moved onto using grassmaps RVT sourcing inside PCG as it seems just as fast and less problematic (always up to date vs physics).
Rebuilding The Landscape Physical Materials was indeed the solution. Oddly enough when I do it manually through The Editor it will not work. I had to wait for the prompt that pops up that notices the landscape needs rebuilt(which was annoying as there doesn’t seem to be a consistent way to get the landscape tp notice it is out of date and needs updated).