Horses jump height much lower after 1.8.9 to 1.9 update

I have been breeding horses and gathering wild ones and testing them thoroughly for run speed and jump height. I have been trying to breed faster higher jumpers. I have two "breeder" horses, one with a jump height of 5-1/8 blocks and the other with a jump height of 4-3/8. After updating to 1.9 the 5-1/8 jumper now only jumps 4-5/8 blocks and the 4-3/8 only jumps 3-7/8 blocks.
Run speed and health have not changed. Is this a bug with 1.9 or was the jump-height mechanic changed/nerfed?