Apologies if this has been asked before (not even sure if I've asked it in the past)

How can I overwrite landscape weightmaps? If I let Houdini create a new terrain, then everything works fine, it find the landscape layer and write the masks as expected. But if I try to apply it an existing one that's in the scene I get some garbled results, like it's writing masks to the wrong layers and there seems to be no logic to what layers it picks from what I can see.

To clarify cos of unreals confusing naming system - I am talking about paint layers specifically