Scaffolding cannot be climbed properly against trapdoor in certain cases

If you place a scaffolding against a solid block, you can go up it by holding forward. This also works with non-full blocks, such as a trapdoor. however, if you place a scaffolding block in the air to the side of the block you're trying to climb, you will not be able to climb all the way up onto the trapdoor when you're too close to the middle of the two blocks.