Not sure if this occurs in 1.17.10, but when I was holding a shield in my main hand, it was inside of my body in third person and in first person, it blocked the top left corner of my FOV. 

Steps to Reproduce:

1. Grab a shield from your inventory.
2. Hold it in your right hand.

Expected results: The shield should be near the bottom right corner.

Observed results (1): The shield is blocking the top left corner of my FOV.

Observed results (2): Works as expected.