Netherite Armor grants no knockback resistance

When I have my netherite armor on, I take no knockback resistance.

HOW TO REPRODUCE:

1. Take a hit with a Knockback II weapon and record the results.
2. Equip a full set on netherite armor.
3. Repeat step 1.

EXPECTED RESULTS:

I take less knockback with netherite armor equipped than without.

ACTUAL RESULTS:

I take the same amount of knockback no matter what kind of armor I have equipped.