Ekko ult bug.

I have been playing several games on full tank jungle Ekko. I had noticed that my ult was not working properly. It seems like the invulnerability was not blocking cc or any kind of damage was interrupting the return to the shadow. Once it was activated I would just ult in place without returning to my shadow. The same thing had happened 3 times in the same game one of the times I was backed into a wall when my ult did not work. I'm not sure whether I was cced or dealt damage to but it looked like I got stuck against the wall. Is anyone else noticing this problem?