Bug bug 1 the stone stairs have 3 different stairs cobblestone and mossy stone .... And when u quit to title the hold world desapears

Ok so i was playing pe and i make a mine and then i go to the title to change the difficulty then i go to load me world and my mine disapears........ The the stairs on cretive the stone stairs i put one and appearse a cobblestone stairs and then i put another and appears a mossy stone stairs??? Need 0.6.0 rev 2 like the 0.3.3 version plz