This is another error found in versions prior to 1.20 and 1.19, I don't remember the version but since then this problem has persisted, it is that when protecting yourself with the listener crouching, it does not protect after approximately 0.5 seconds or so , I have to take cover and wait like 1 second for the Shield to protect me, I have lost a lot of progress from local survival worlds that I have had because of this problem, it is very annoying to be dealing with this since I literally have the Shield in front of me, It should be protected and no, since having the Shield protecting me, hostile mobs can still hurt me.  You crouch and have to wait a long time to cover yourself with the Shield.  If it is a change that they made officially, could they make me understand if I was wrong and I am not reporting an error.