Creepers not pulled down by Magma Blocks in 1 high bubble water

Creepers are not pulled down by Magma Blocks consistently in 1 high bubble water whereas other mobs are. They seem to have to bop up to a certain height and fall back down again before they are then pulled down.
I assume this is an issue with them being 1.5 blocks tall?
This seems to have been an issue since the bubble columns were released.