Blue Buff Visual Bug

In the game I linked, I was the Lulu and noticed something odd. Firstly, the Nidalee on our team came to bot lane to gank with blue buff. She ended up dying and passing it on to Caitlyn. Then, my ezreal proceeded to kill the Caitlyn and the blue buff transferred as expected. Then, when we all re-spawned and arrived back in lane, I noticed that Caitlyn still had the blue buff aura. I clicked on her and saw that the blue buff passive was not there, but it still displayed graphically. My ezreal had the actual blue buff as intended, but this visual bug persisted throughout the entire game. I don't believe it caused any obvious disadvantages for our team, but suffice it to say, we still freaked out a little bit thinking "OMG WTF INFINITE BLUE BUFF OP OP!" Unfortunately, I don't have any screenshots or video proof.