Yorick phasing through walls

In my last game as Yorick i was ganked in the jungle and during the fight i somehow was able to walk through the wall from below the blue buff to the pit where it spawns.

I never play this champion so i dont know if this a known issue or not but i watched the recording of the game several times and yorick did not flash or get pushed over the wall; he walked through it. several other people in the game saw it happen.

Edit: Now with video https://www.youtube.com/watch?v=LBOJIOlzNeM&feature=youtu.be