The Bug:

Wolves render their held mainhand and offhand items.

Steps to Reproduce:

1. Create a flat world with the game rule "Mob Spawning" off.
2. Summon a wolf.
3. Run command: /replaceitem entity @e[type=wolf] slot.weapon.mainhand 1 bow
4. Run command: /replaceitem entity @e[type=wolf] slot.weapon.offhand 1 shield

Expected Results:

Wolves will not render their mainhand and their offhand held items.

Observed Results:

Wolves will render their mainhand and their offhand held items.