Blazes don't hover up and down constantly, just stay in one place

When blazes attack and fly above the player (when the player is in survival mode), instead of hovering up and down continuously, they hover in place without moving at all, as if a player was standing still in creative mode midair. The blaze hovers up and down, but when it is hovering in one place, it doesn't bob up and down like it does in 1.7.10. It changes height every now and then and looks awkward.