Drowned mobs just walk up full blocks instead of jumping onto them

The bug

Normally, mobs have to jump when they want to go onto a higher full block. But when there is a drowned mob, no matter if it spawned naturally or by a spawn egg, it will just walk up onto higher blocks without jumping.

How to reproduce

1) Spawn a drowned
2) Go to survival mode, so the drowned chases you
3) Jump onto higher blocks and you will notice that the drowned just walks up onto them