The Bug:
Amethyst buds and clusters cannot be placed on honey blocks.
Steps to Reproduce:
Attempt to place a spore blossom on the underside of a honey block.
→ ✔ Notice how you are able to do so.Attempt to place an amethyst cluster/bud on any side of a honey block.
→ ❌ Notice how you are unable to do so.
Information:
Since spore blossoms can be supported by honey blocks, I'd expect the same behavior for amethyst buds and clusters.
The real bug here is why you can place blossoms on the honey block, you shouldn't be able to since it is not a full block.