Possibly Interaction Issue with Kennen and Yasuo

So I started playing Kennen about a month ago, and I noticed something when I would play against a Yasuo. When I would auto him when I have the electric surge passive to do more damage, and apply a mark of the storm, if he blocked it with his wind wall, I did not lose the stack. Like, he stopped the auto, but it did not remove the passive that I had built up from Kennen's W. I noticed it about 2 days ago, and I have been seeing it ever since. Is this something that anyone else has been seeing, or is it just something I am missing in my game?