ARAM - Oracles Glitch ?

I was just playing and ARAM match and was playing as Darius.

We were against a Teemo and a teammate suggested Oracles so I got it since I had just died in lane.

I had it on and then it ran out, causing us to lose some team fights, so I went and bought another one. Another 5 minutes passes and I noticed it ran out.

Now I don't know what exactly happened leading up to my death and when the Elixir ran out but after I came back I had forgot to re-buy it. However, I noticed that I could still see teemos mushrooms! Although it was more like it use to be. you see then when you get close but not through bushes and such [Which I actually like] even though my oracles ran out I could still see the traps when I got close, although when face checking bushes I'd still get hit once or twice but it allowed me to clear the field even though I didn't technically have the buff anymore.

Hopefully Riot looks into this, could be abused if someone figures out how to cause it.