I've experienced mobs having a hard time pathfinding up a block, mobs like lions can be cheesed with it, but also it makes leading mobs a massive pain
Asked on discord if anyone else has had it, and other players reported it too

This happens mostly if the block the animal wants to jump up has either fallen leaves or at least a double thick snow layer on top of it, both have hitboxes that prevent most animals from being leaded up them.

This also happens if the mob is standing on a similar block (or touches it). I removed all the blocks under the mob and he calmly jumped even on blocks with sticks, stones, plants, snow, etc.

#2521
#2520