Well, I'm not sure if this was a once in a life time bug (since it's gonna take ages to start a new game and get another DE) but my Diliverance Engines fail to do anything to enemy culture etc.

So here are the steps I did to get the believed bug.(Map is Ancient Gifts i believe)

1. Built a DE on the bottem-right star system in the terran planet's grav well.

2. Built the DE behind the planet so it would have to shoot thru the planet to hit the others.

3. Upon firing, the shot went thru the planet and then i couldnt see the icon to select it so i could track it. (almost as if it disapeared as my projectile but i could still see it).

4. I thought it was odd so i started massing DEs all over the map only to have all of them do nothing, but they did have my icon over them this time.

I'm gonna try replicate this again some time soon but if anyone else can confirm before then... much appreciated