Villagers get trapped in seaweed

My villagers tend to go swimming, but some stay out there because they are "trapped" in the seaweed. They think they're stuck in a full block & decide not to move, yet they are still able to stay above water & bob around.

I don't know if this includes other mobs, and/or if other water-based/water-logged blocks carry the same effect.

Attached is the example of a villager getting trapped.