Players with increased step height can fall off blocks while sneaking, even when stepping back up is impossible

The Bug

When sneaking till the edge of a block n blocks above ground (where n is at least the height of the player) with the attribute "minecraft:generic.step_height" set to at least n, you'll fall down, even when stepping back up is impossible.

What I expected to happen was...:
The player will not fall off the platform

What actually happened was...:
The player falls

Steps to reproduce:

1. Place a block 2 blocks above ground and stand on it

2. Do

   /give @s minecraft:golden_helmet[minecraft:attribute_modifiers=[{type:'minecraft:generic.step_height',id:'1',amount:2.4,operation:'add_value',slot:head}]]

   and apply the helmet.

3. Sneak towards the edge of the block
   (watch video )