[Cross-posted from http://beta.leagueoflegends.com/boar...t=15443&page=5 to make sure that Riot sees it without having to chain-bump that thread.]
So, here's a pathing problem that I discovered.
The red highlighted enemy is the one I'm trying to attack. You can see where I am in the screenshot. The pathing wants very badly for me to walk through the wall.
It's worth pointing out that I wasn't standing in that exact spot the first time I clicked to attack, I was standing a little bit up and a hair to the right. Then I tried again from that spot, and apparently the same pathing issue applied.
(I hope this helps Riot.)