This BUG actually happens in both Survival and Creative mode, but since creative has unlimited resources, it is not that bad, but it really is a pain in the ass when you are trying to harvest some flint from the gravel and all of them simply disappears(without even dropping the original block! I hope this can be fixed in the next update. Thank you Mojang. Minecraft is a great game, no matter the PC,PE or XBOX, they are great and keep up the Great work!