When the Main hand is set to left the sweep animation still plays right handed

I am using left as my main hand. When I do a standard hit on a mob with a sword the right handed sweep animation plays. I expected the left handed sweep animation to play. Instead the right handed sweep animation played.

Steps to Reproduce:
1. launcher minecraft in the affected versions
2. click options -> Skin Customization.
3. set main hand to left
4. open a creative world
5. grab a sword and a mob egg
6. spawn mob and hit with sword

The animation should play right handed