Saw Sivir Almost All Game

I didn't manage to get a screenshot, but my entire team, in a match could see the enemy Sivir almost all game. I didn't notice it until about 15-20 minutes into the match when our Caitlin pointed it out. We saw her all the way from spawn to, down the lane, into the jungle, into bushes; pretty much anywhere she went. There were no wards around her and no halo of vision where we could see anything else around her (unless our minions or something else of ours actually meant to give vision, gave vision). I believe this happened after Caitlin had ulted her as she was running out of normal vision range, and Sivir then used her shield to block the shot. I'm not sure if that's what triggered it exactly, but that's what I'm speculating. Made the match a bit unfair, but we were winning heavily by that point anyway so there probably wasn't much they could do.