Hello 👋
I sometimes see ByG or project vibrant journeys ground blocks spawning on top of the no tree punching rock blocks.
I asked them and they said that the problem was how the rock was set, so apparently there is a way to set the properties of this block to forbid anything spawning on top of it.

Here is a picture for example :

That's a vibrant journeys plant spawning on top of this rock.

I'm using minecraft 1.16.5
Forge 36.2.9
notreepunching-forge-1.16.5-4.2.3

I don't quite understand how this is occurring. There's two scenarios:

1. Loose rocks are placing on top of existing features - this shouldn't be possible, loose rocks already explicitly check and will only replace blocks that return true to BlockState#isAir, and will only place on blocks explicitly whitelisted in the #notreepunching:loose_rock_placeable_on tag.
2. Other features are placing on top of loose rocks - The other feature should do adequate checks (which to the extent I can see, for instance, PVJ already does - they check if the collision shape is a full block, and if the block has a solid render (a bit of an odd check, but NTP returns true to both of those. And I don't see what properties my block is missing that would incorrectly mark it as "solid ground".

I have no idea either why this is occuring. An easy way to test it out is to download ByG and
/locatebiome byg:cherry_blossom_forest

There you can find white cherry foliage on the ground, they will spawn on top of pebbles and float weirdly just like this

The screenshot was taken on 1.16.5
byg-1.3.5
notreepunching-forge-1.16.5-4.3.0
Forge 36.2.34

If that can help...This biome in particular has a lot of leaf carpet spawning on top of the pebbles

Sorry, I'm not supporting 1.16.x anymore - if the issue persists in the latest version (1.18.x), please mention or open a new issue.