A vicious BUG with shield

Although from version 1.11 the shield can withstand 100% of the damage，using shields to block attacks still damages the durability of the armor worn by the player, and does not know if it was designed intentionally.
And the BUG existed long ago, and it was said that the original defense against the sword had not been completely removed, which led to the emergence of the BUG,I hope you can fix it later