Use redstone machine can get infinty items!

I am Chinese but I don't play the netease edition ,so maybe my english is not enough to speak this bug ,but I think I can let you know what the bug like.
when i play a minecraft server ,I find a bug .The bug is use dropper or dispenser with some redstone [like the picture]can get infinty item
1.Create a machine like the picture
2.put some item[at least 10] in it
3.stand at the dropper or dispenser to pick up the item
4.open the crafttable , click the item , and click the 3x3 craftgui,then the item will x2
that's all , i hope mojang can fix the bug, the bug is bad for us server!