Anyone else experience this glitch?

I've noticed that twitch and evelynn can get way closer than their wikis say they can before the stealth disappears. The wiki says visible to champions within 700 units for twitch and evelynn both. however I've had times where they just show up right next to me, well within 700 units without any warning. Is there some kind of motion check/awareness behind the scenes or is this a legit bug?