Soul speed doesn't work when slabs and blocks of similar height are placed above the soul sand block

The bug

If there's a slab on top of soul sand, the soul speed enchant doesn't work and slows you down as if you don't have the enchantment.

Affected blocks

• Slabs
• Daylight sensors
• Lower part of the stairs
• Snow with 3+ layers of height
• Cakes

Example

Here is an example in video: 2020-03-12 02-58-11.mkv