Several blocks are incorrectly ignored by certain heightmaps, and a couple are incorrectly included in certain heightmaps. Not only is this an issue when using commands, but the fact that the motion_blocking heightmap controls which blocks rain and snow can fall through leads to incorrect behavior for the affected blocks.

The following solid blocks are incorrectly ignored by motion_blocking, motion_blocking_no_leaves and ocean_floor:

• Azalea (regular and flowering)
• Big dripleaf (rain/snow ticket: MC-226976)
• Carpet (including moss carpet, rain/snow ticket: MC-203542)
• Candle
• Chorus flower and chorus plant (rain/snow ticket: MC-259109)
• End rod
• Flower pot
• Head/skull (all types)
• Heavy core
• Lily pad
• Redstone comparator
• Redstone repeater
• Sea pickle
• Snow layer (level 2+)

The following non-solid blocks are incorrectly present in MB, MBNL and OF:

• Banner (the half with the block itself, rain/snow ticket: MC-260599)
• Dead coral (all types, rain/snow ticket: MC-248299)
• Sculk vein (rain/snow ticket: MC-258779)
• Wall sign (rain/snow ticket: MC-248890)

The following movement-impairing non-solid blocks are ignored by MB, MBNL and OF, which is probably intentional with the exception of powder snow:

• Berry bush
• Cobweb
• Powder snow (rain/snow ticket: MC-205442; should be treated the same way water and lava are By MB and MBNL; I'm unsure whether OF should also ignore it)
• Vines (normal, twisting and weeping)

The following special cases are worth mentioning:

• Scaffolding is ignored my MB, MBNL and OF. I'm unsure whether this would be intentional; it's somewhat understandable that rain and snow can fall through it, but it would be equally understandable if rain and snow landed on it. Also, scaffolding does block the motion of falling and standing entities, but in other respects it doesn't. Either way is probably fine honestly.
• All heightmaps, including world_surface, fail to account for the collision box of a fence, fence gate or wall. This could be considered intentional, but in the context of commands, these heightmaps are mainly useful as a means of identifying the topmost space above the ground in which an entity would not be inside a solid block, so for that reason it may be better to ignore any open space directly above these blocks.
• The top part of an open shulker box is also ignored by all heightmaps, but I assume this won't be fixed since rain and snow passing through it is probably intentional and the gameplay impact of the remainder of the issue is essentially zero.
• The top part of a banner placed on the ground is ignored by world_surface. This seems inconsistent with other non-solid blocks, and the best way to fix it is probably to simply make the banner 2 blocks tall (although care would need to be taken to preserve world upgradability).

To Reproduce

1. Find some surface grass and place an azalea on it
2. Stand on the azalea, right in the middle

3. /execute positioned over motion_blocking run teleport @s ~ ~ ~

   You are teleported into the azalea

Expected Behavior

You would remain on top of the azalea