For a comprehensive list of other examples of issues with item positions in the Creative inventory, click here.

All tickets associated with item placement in the Creative inventory are valid for cases introduced in 1.16 and later as per this comment. Exceptions exist, which are valid for their own reasons.

The bug

These blocks, added in 1.16, have raw "normal" variants, as well as specifically titled "polished" variants. As such, it would be expected that they would be placed at the top of the creative inventory, as four other stone types of that specific description also are. However, they are instead found much farther down.

It may also be worth noting on the side that smooth basalt is grouped with other basalt variants, whereas smooth stone is not grouped with stone itself.

How to reproduce

1. Open the Creative inventory
2. Locate Polished Deepslate in Building Blocks
3. Locate Polished Blackstone in Building Blocks
4. Locate Polished Basalt in Building Blocks
5. Note that there is a considerable distance between these items