Doublechecked after it was pointed out by xisumavoid in a recent video, but in 21w37a where this fix was made it seems like this isn't currently working on sheep.
This can be more easily scene when you have a Dinnerbone/Grumm sheep and cow right next to each other, you hold a piece of wheat in your hand, and then you jump up and down. You can see that the Cow will look up at you while jumping, but the sheep will tilt its head back into the ground.
Can confirm this as still present in snapshot 21w41a.