Items misplaced

This problem is getting bigger my items in game made by me or found by me are getting misplaced its happening from version 1.16.100.53 and continue whenever I close my game and next day when I play the items are misplaced even after creating ther bakup/copy the items created in original world is not even discovered in copy world(here i have created a full iron armour but I am only left with helmet). Apart from this drowned is wearing golden helmet even he had no given any. I request mojang to please look into it so we can peace fully and enjoy playing minecraft.