Hi,
I've got the same problem as you.
Unfortunately, if I remember well, I had the same problem on the official game server for the same version of the game.
I think it's more a game problem than user. Firewalls, overlays, mouses or graphic cards drivers won't change anything of the problem.
I'll try to look on the french forum of Aion official game, I think (again if my memory is not bad ) I saw a topic at the time, if I find it, I will edit this post.
Edit : My memory is good. I've found some old topics about that :
Link 1
Link 2
Link 3
To summarize the topics above, there is no real solution, most of people who got the problem used Razer gaming mouse. But for example, I've never used Razer brand mouses, and got it too. May be it's simply as I said, the game, with "new technologie" mouses ^^. Some players said that with old old mouses they don't have the problem anymore so... let's try PS2 mouse haha.
Sorry (I am disappointed too)
Regards