Java parity issue from MC-249691.
While grass blocks are grouped together with dirt blocks in the Creative inventory, the same is not true for nylium with netherrack.
How to Reproduce
1. Open creative inventory on the nature tab.
2. Find grass blocks and dirt in the creative inventory.
3. Find nylium blocks and netherrack in the creative inventory and compare it with the grass blocks and dirt grouping.
Observed 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 at the bottom.
Expected Results
Netherrack and nylium should be grouped together.
The fix wasn't even pushed yet. It might be wise to wait until that's done before creating a "future parity issue report" next time.
Changes like this are easy to synchronize across editions, and that was likely already done in the development builds.
Strictly speaking, you just reported a parity issue you're not even sure will exist.