[Gameplay] Possible bug: Sona E not speeding up champs/ or only Corki

I was playing with my friends and I noticed that when I tried to speed up a friendly Corki, he didnt gain any extra movement speed, nor did his speed boost animation go off and moved at the same speed as he normally did. This happened in two separate games. I noticed it did work on other champs, but I didn't look more into it. So i dont know if it doesnt speed up on every use, or only on some uses.

If you want to try and recreate it, just Be Sona, use your speed boost on a Corki. If it means anything, we were next to a destroyed mid inhib turret.

Can someone confirm if this is in fact a bug, or just one of those one-time rare occurrences?