Description:

Evoker mob doesn't have the particles above the left hand when it summons the vexes or the fangs.

You can experience the bug if you do the following:

1. Spawn an evoker mob.
2. Spawn a villager or go into survival mode.
3. Wait for the attacking moment.
4. You can now see the problem, the particles only appearing above the right hand.

I attached a picture for better understanding.