Fizz can use his E to get through Veigar E without being stunned, after the walls are up. This used to not be the case and how I killed many an amateur Fizz but since the Veigar update, this seems to be happening. I don't have evidence but I imagine it's pretty straightforward to recreate.
Plis. Veigar been nerfed enough :(
http://leagueoflegends.wikia.com/wiki/Dash
Says here "technically" it shouldn't go through. So yea...
I would have expected Fizz to be able to E through Veigar's wall. It makes him untargetable - new abilities do not affect him. It would actually be stranger if he wasn't allowed to.
I mean, it makes him untargetable. I'd say make a custom game with a friend who has Vlad and see if Vlad can pool through it. If he can, it's working as intended. If not, then Fizz's E is bugged.
uh.... I've played Fizz and have E'd through a Veigar E many times even before the rework.
Yeah I noticed a different issue with Fizz's E (Playful / Trickster) so maybe something changed recently that is making it work not quite correctly (Though I'd agree with QETZEL that it makes sense for Fizz's E to be able to go through Veigar's wall).
Anything that isn't a dash should go through
