The bug

While grass blocks are grouped with dirt blocks in the Creative inventory, the same is not true for nylium with netherrack.

How to reproduce

1. Open Building Blocks
2. Locate grass blocks
3. Locate dirt
4. Locate nylium
5. Locate netherrack

Expected results

Dirt and grass blocks would be close together, and netherrack and nylium would also be.

Actual results

Dirt and grass blocks are next to each other, but netherrack is very far from nylium; nylium appears near the top whereas netherrack is around halfway down.

Further notes

Likely worth noting is that mycelium is far from dirt as well, however this predates 1.16 considerably.