{{champion:8}}Vlad E triggers too early

So I discovered this in a custom game in Howling abyss, I don't play Vlad often but I know his kit. I was playing against an Ivern and noticed that when I started charging my E, it would instantly trigger. I didn't think anything of it until it occurred over and over severely reducing Vlad's damage output. I know that Daisy's knock-up cancels the e, but even when Daisy wasn't out it occurred. The frequency of this bug takes the fun out of a really cool champion, by being unsure if your own kit could fail you.