Hi! I have this same bug and can't find a more relevant thread than this one, I only found some that are vaguely similar but with different specifics (or less information).
What happens is build mode works for a while normally, until the bug occurs at which point nothing can be placed, moved, or otherwise altered at all. Undo etc does not work. It always triggered after editing roof and wall pieces. Reloading the game will let it work for a short while, but the glitch happens again very quickly (though not after a set number of items placed/moved). There are no error messages at all. I had the bug in Everdew on the Watering Hole lot, in Innisgreen. I encountered this bug a couple weeks ago (before the Sept 18th patch), and got frustrated enough that I just haven't done much with build mode since then.
I'm on PC Steam, with no mods/cc.
Additionally, this bug was shown in James Turner's recent video; https://youtu.be/k0fxrJSFP_o?si=hMwammifZ_H6nkwQ&t=2442 (This should link to the relevant portion, but it's at about 40min if not.) Note he questioned if it was the water in the video, because of an earlier issue that did come from building over a pond, but I was not building over a pond when encountering this bug.