Sometimes Entering a World You lose all you Stuff

So My World Called Pocket Survival S1 One time i entered the world the suddenly ALL my stuff is gone So yeah i didnt cheat or hack And on the (2012) Model of the Kindle fire hd 7 the bug
also happens when you go on pocketinveditor and get 255 items of example:dirt suddenly when you load the world all your items are gone So yeah! P.S Im using the 2013 model of the asus nexus 7