Mobs don't path find across powder snow blocks when not wandering

Happens even for mobs that don't fall through powder snow, such as zombies with leather boots or silverfish, which means pushing these mobs on top of powder snow breaks their pathfinding completely.

They will however pathfind over the powdered snow if the blocks beneath it provides a valid path. Albeit if they have leather boots on, their pathfinding will get confused resulting in them often spinning around in circles as described in this bugreport. MC-205083

Can confirm in 20w51a.

Can confirm in 21w03a.

Can confirm in 21w05a.