After disabling a shield the player whose shield was disabled has an invisible invincibility frame.

When someone's shield is disabled they should either not have an invisibility frame and therefore can take knockback from a weak hit or the player's skin should turn red for 10 ticks as it does for normal invincibility frames.

Steps to Reproduce:
1. Go into a vanilla multiplayer server with another player 
2. Have the other player hold a shield while you hold an axe
3. Disable their shield with an axe and quickly click a second time before 10 ticks has passed