Steps to Reproduce:

1- Get a shield and be in suvival mode

2- Find a mob that can melee attack you (ex: Zombies, piglins etc) 

3- While blocking with the shield let the mob hit it 

Observed results:

• The mob get knock back by a 1 block

Expected results:

• The should not get knock back at all

Note: This was in java edition before 1.14.4