Curtain Door Related Issues

I decided to build a curtain door on the tile a door was standing in, thinking it would just layer a curtain over the door or something like that, however the building of the curtain door on the tile of the actual door just evaporated the actual door and replaced it with a curtain one. The door is not de-constructed, it’s just removed from existence entirely.

De-constructing the curtain door left me with a tile that is just called “nothing.” Another door is not build-able on this tile, but I am able to walk over it and I’m able to drop items on it. After save-scumming, smashing the door leaves a dirt tile under it as it should, and I built another door on the site.