Evelynn's not so invisible to Heimer

To put it simply, i did an ARAM, t'was fun, yeah yeah. Only problem was, I was playing Eve, and there was Heimer in the enemy team. "Okay, I just have to stay out of range of his turrets while I'm revealed, that's not a big deal." Yeah sure, bullshit. While I was just walking near his turrets and was NOWHERE NEAR ANYONE or used any attack, the turret just aimed at me (Like, for them there was absolutely nothing at all in the way it was facing) and shot its laser, breaking the invisibility. I'd have no problem with that if there was a justification, but there is none. The only thing I can see is that the turret's field of vision is somehow related to a champion's, but then problem again, it shoots while nothing says that I could be seen by even a damn poro! So if anyone find out why, please explain it, because if the turrets can bullet-rape an invisible foe, I'm buying Heimer ASAP.