Feeding tamed baby wolves and cats causes them to sit down/stand up

When a kitten is fed fish or a puppy fed meat, the food item is consumed and the pet grows older, but no growing particles are emitted and the kitten/puppy will still stand up or sit down (unlike an adult pet, which remains in its pose when fed).

What I expected to happen:

Kittens are supposed to consume fish without also standing up or sitting down, and they should show green growing particles (the same as with bonemeal) when fed. Same for puppies consuming meat.

What actually happens:

Kittens will consume fish (the eat sound plays) but they don't show the effect of being grown, nor does feeding block the sit/stand interaction. 

Steps to reproduce:

1. Spawn or find a kitten
2. Tame the kitten
3. Feed the kitten fish
    The fish consume sound plays
    No green particles appear
    The kitten sits down/stands up

Video:

Here's a video