Scaffolding does not Count Blocks with an Uneven Top as Support

If scaffolding is placed on a block whose collision box is aligned with the top of its voxel, but is not flat, the scaffolding will not see that block as a lower support and remain a falling block entity.
This does not happen for other gravity-affected blocks (sand, gravel, anvils, concrete powder).

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To reproduce this behavior, place/drop a scaffolding block on top of one of the following blocks with collision:

• Hopper

• Cauldron

• Anvil

• Iron Bar or Glass Pane (same collision box)

• Bell

• Grindstone

• Open Trapdoor

• Door

• Stair (half=bottom)

• Bamboo