The new baby Villager model has an 1 added to the X axis in all bone pivots, causing all rotations in the Y and Z axes to be incorrect.
Most animations in the game rotate the X axis so the issue is not very noticeable in the game, but it is very visible when the baby villager looks to the side.
This can be fixed by subtracting 1.0 from the X pivot in all bones of the baby villager model. I have attached a version of the model file with the fix applied.