duplication glitch minecraft

He duplication glitch minecraft
He put item on chest and save the game
And cilck to play map again and mine block 6 block and leave game(Alt+F4)
And back get the free item in chest can you fix it?
(My Account xbox is timemimi089)
Full video:https://youtu.be/5xH_eMqksIE?si=7gDVAuVcg4rya4-l