Issues with feature placement generation

It seems there is an error with the software's generation of feature placements. I'm trying to generate a vegetation patch feature that can be pasted in fine using commands, but doesn't generate during worldgen.

Why? Because there is no placement.

Somehow, even if I use a preset generated placement, it isn't generated, and is written as an empty set [ ] instead.

Any solutions for this? I have a lot of different features to code in and I don't want to lock every one of them manually. I'm working on 2025.2.