Not true.
That may be how it's supposed to work, but that's not how it is currently working.
If the AE hit you when the marker disappeared, you wouldn't be hearing so many complaints about it. The fact is, you can get out of the area
well before the marker disappears and still get nailed with an AE move. There is plenty of evidence of people moving out of AE's before the target marker disappears and still getting hit.
Here is a glaring example:
http://www.youtube.com/watch?v=G5g4TM1fkCg
Obviously it becomes more of an issue the higher your ping, but
It's the games fault, not the players. I ALWAYS have a 60 or lower ping, and I can reproduce getting hit while being out of the marker 100% of the time.
The game does not update player position properly and that's causing the problem. Don't believe me? Test it yourself. Find a mob that does an AE, stand in it until the last couple of seconds then move...you'll get hit. Now do it again, but as soon as you move out of the AE hit an instant cast spell...you won't get hit. Why? Because the game updates your position when you use an ability, but it doesn't automatically update your position when you are moving. This is a MASSIVE problem with the game that isn't going to solve itself by telling others what amounts to "you're doing it wrong". It would be a whole lot more helpful if people just admitted that there is a problem and we all got SE to notice and work on it, instead of half the community blaming the other for being bad, or not understanding how these things work.