Dublicating items with silk touch pickaxe

You can dublicate blocks like beacon, ender chest, cauldron, note block and jukebox with silk touch pickaxe. The bug happens on the device Xiaomi Redmi Note 4X but my friend who has Samsung phone experienced the same bug. First I saw the bug in realms server but then tried it in singleplayer and it still works. The bug is present to me from version 1.2.9