Mobs jump when they get near chains, end rods, bamboos, lightning rods or pointed dripstone

If you have a mob near a chain sometimes they will jump

It seems like they think they are full blocks (this can be supported by the fact they won't leave the chains, but I doubt this is fixable per MC-21109). When they get too close, they jump around a lot.

Video example: https://www.youtube.com/watch?v=eUz9D_hK2zo