The player does not receive an instant slow after jumping onto the edge of the soul sand and honey block

When you jump on a soul sand block, you cannot immediately perform a long jump. However, if you jump to the edge of a block, you can make a long jump, without being slowed down immediately.

Just pick up speed and hold the jump button, video demonstrating the issue: https://youtu.be/rjcUtM3J9CQ

It's the same with the honey block, in the video, if you jump in the middle, you won't be able to reach the ladder.
However, if you decide to jump on the edge of the block, you will be able to reach the ladder.
Video: https://youtu.be/5l0vljcILQs