Reporting Zed's bug

I usually played Zed. But, one day, bug happened. After I use W(Living Shadow) active Q(Razor Shuriken), I can throw two Q(one is Zed's, the other is shadow's). I also can see two Q's two traces. But, after W is gone, I tried to use Q again. Then, the trace must be one. However, the traces was still two, and I just can throw only Q of Zed, not Q of shadow which had gone. This bug makes me confuse when I play Zed, and I want you to fix it as soon as possible.