Players and skeletons hold bows differently

The bug:
Skeletons hold bows with their arm straight down as if "resting". When a player holds a bow, the arm is slightly elevated like with other items.

How to reproduce:

1. In creative mode, spawn a skeleton. Notice the skeleton's arm position.
2. Equip a bow yourself, and take note of the difference between the way the player holds a bow vs the skeleton.