SE has acknowledged the orange Area of Effect (AoE) attack lines are misleading - whether you have actually cleared an attack is by the enemy's attack charge bar that appears on their target bar. The orange lines may still be up, but if the charge bar has vanished, you've failed to clear it. This is due to latency between the server and your computer/PS3. Unfortunately, there's not much that can be done about this, other than to try and be more reflexive when it comes to enemy attacks (don't worry, as a tank too I know this feeling all too well sadly).