Everytime I save and close a survival map, the next time I open it, half of the items in my chest just disappear.

I created a survival map, went mining, got everything and put in one big chest, upper half with minerals and the bottom half with block, saved and finished for the day, next day open the world look at the chest and just the upper half is there, all the blocks are gone. Deleted this map because of pure disappointment. Tried doing again, other map, other day, divided my chest the same upper half minerals and bottom blocks, save and finish for the day, opened today, bottom half totally cleaned. It's just dissapoint half of all your work gone.