Underwater, skeletons can shoot players with shields from underneath

Despite having a shield raised and looking right at him, the skeleton was still able to shoot and kill me

What I expected to happen was...:
As the first person view showed my shield raised, I was expecting the arrows to be deflected as normal.

What actually happened was...:
The skeleton was still able to shoot me.

Steps to Reproduce:
1. Spawn a skeleton in any body of water four blocks deep or deeper.
2. Swim above the skeleton and switch to survival
3. Raise your shield while looking at the top of the skeleton's head