I have a pair of Netherite Boots I recently enchanted with Soul Speed 2 and took for a ride on the Nether.

It works as expected on Soul Soil and flat surfaces of Soul Sand, but is very inconsistent when climbing Soul Sand, specially when trying to navigate mountainous terrain. The player seems to get stuck on the edge of a Soul Sand block and is pushed backwards towards the adjacent lower block, briefly cancelling all momentum from running or walking. Once the player loses momentum on the edge of a block, the two forces cancel each other and the player is incapable of going forward without jumping.

I've attached two videos, on the first one demonstrates me being pushed off a cliff into a lava pool and being unable to get out because of the backwards force, the second one demonstrates the effect more clearly from a third person perspective.

To reproduce:

1. Equip soul speed boots
2. Try to scale a Soul Sand block while standing on a Soul Sand block