Playing on the Windows 10 Edition with the Pocket Edition UI. Would like the Xbox UI... But that's beside the point. When in a crafting table, furnace, or chest my hotbar will generate false duplicates of a certain item in every slot. They don't actually duplicate though. For instance:

If I had 5 blocks of dirt, they would be duplicated to every (or almost every) slot in the hotbar. But when placing a dirt block, they all reduce to 4.