Looks like you are using GrowingAge and not IsChild to determine if the EntityAnimal is a baby:

@Override public Predicate<Entity> getSelector() { return var1 -> var1 instanceof EntityAnimal && ((EntityAnimal) var1).getGrowingAge() == 0; }

Any particular reason for this? I mean I can set my entities to have a negative GrowingAge, but seems a bit odd since the IsChild flag is right there....

fixed in 1.12

Cheers @williewillus