I just set up my first game last week. One of my players reported this happening twice. After the Ferrengi is destroyed, it gets one last shot in.

Did I mess with some delay value so much that he's killing the Ferrengi after it fires and before he gets hit?

without a screen cap, or your delay settings, can't be sure. BUT i will venture a guess and either there maybe was some lag and the message came after he was blown, but he shot before he was blown, or he just killed him so fast that the message came late. OR (and this is a guess) it COULD possibly have to do with having interactive subs turned to off and the message was delayed because he sat on the attack y/n prompt.
those are my guesses.

Slim

There is quite a bit of difference between the time that an event takes place within the game and the time it is displayed on the screen. The order of events are definitely well known within the game, so if the Ferrengi had been destroyed, it would not have been able to launch one other attack. But it's certainly possible that the Ferrengi attack was comleted before you destroyed the ship, but the output was not displayed until after the ship was destroyed.