On my lan server {hear me out}: Went mining in this world found a minshaft with a chest in a mine cart. took all the conents of that chest and took the chest and mine cart as well. Went back to the surface place down that chest and put all the contents of my inventory of cobblestone, dimonds, lapis, redstone, ect. then did some farming and other routine matinace around the base planted crops and chopped down trees. Logged off and came back on to notice after about 5 minutes the chest I had was no longer there and all the contents there of were gone. but all the work around the base was still done making it not a roll back or something.