When the player performs a mace smash attack by falling from certain height, the smash attack knockback is applied to mobs in a certain radius, but also applies knockback to entities behind blocks.

May or not be a bug since this doesn't happen with wind charges and the knockback from both sources behave kinda similar.

How to reproduce

1. Place 2 armor stands, separated by a wall made of solid blocks.
2. Equip the mace and perform a critical hit from a certain height to one of the armor stands.
3. Notice how the other armor stand was knocked back, even if it was blocked by a wall.