Ryze's 1st ability "Overload" doesn't show mana cost properly

I think the title/image explain it. I did notice that if you're out of mana the cost does appear, not sure if that means anything http://i.imgur.com/tZyPy5F.png if you own the champion, plz tell me if the same thing happens to you. thx

quick search on youtube gives me this:

cost DOES appear normally Published on Jun 28, 2016 Published on Jul 18, 2016 Published on Dec 29, 2016

cost DOESN'T appear normally Published on Apr 27, 2017 Published on May 4, 2017