First of all, when a shulker fires a projectile and I block it with my shield Instead of taking no damage and not getting levitation I Take 1 point of damage (no armor) and get the usual levitation debuff. I feel that the projectile should have all damage removed when Shielding and at least have a decreased debuff time.
secondly, I fought a blaze with a shield and when I block a fireball it sets me on fire still even though I blocked the fireball and never even touched the fire that was several blocks away.
This may be related to MC-86344
Fixed somewhere between 15w45a and 15w34c: Potion effects are no longer applied when blocking with shield. I'll create a separate ticket for the fire issue later.
edit: Fire issue actually fixed as well, only fire arrows remain.