Jhin W (passive) visual bug

I just played an ARAM game with Jhin and I noticed a bug with his W.

Enemy Nidalee was marked with W passive, but when I shot her with W, she did not get rooted. Rewatching it after the game, it seems like that the W mark icon I saw wasn't a real mark, just a visual bug. It did not disappear for some reason, when the mark expired.

Here's a quick timeline of things:

• 34:16 Nidalee gets marked
• 34:20 Mark expires, but the visual stays on her
• 34:24 I shoot her, because I see the mark, but she doesn't get rooted (video of this included)
• 34:42 Mark visual still on her, she gets damaged by my basic attack, this resets the mark
• 34:46 Mark visual disappears like intended

Mark is a real party pooper, I'm telling you.