This bug is pertty simple to trigger. I'm Hungarian. On my keyboard @ can be written if the two buttons(Alt Gr + V) are pressed. I use @ at command blocks and I'm really into redstone so I use it a lot. The problem is when I make more complicated machines and need to copy some commands. Then I can't use @, because it works like Ctrl+V and pastes. And when there's nothing copied it's not doing anything. Please repair this bug Mojang. You're screwing over every Hungarian redstoner if not 😛
(Sorry for bad English)
Fixed for a future version. MC-68642