Summary
Firing the bow from the off-hand causes the item to nock an arrow, but the arms do not pull the bow back, similar to the primary hand.

Steps to reproduce
1. Set own gamemode to creative
2. Spawn in a bow
3. Place bow in off-hand slot
4. Hit F5 twice to go into third person (can't really test if other players see this due to MC-88470)
5. Draw the bow back

What I expect to happen
I expect the animation where the player draws a bow back (figure1.png)

What actually happens
The player does not draw the bow back, yet the bow item nocks a bow and draws back (figure2.png)