Duplication glitch

Ok. So its about all the beta version of minecraft. There is a serious glitch that you need to fix that is if you put a item in a beacon in the first 2 layers and keep double clicking it it gets doubled. I have tried it in survival and it still works. Please fix it as it will take away the thrills and fun of getting stuff in the game and with it you only need a one specimen and you can copy it again and again (NOTE:- only works to items that are stackable)