First time I've come across this... I was playing a (basically) 4v1 and i was winning. Someone built a halley and sent it to my planet, but i just thought "i'll nuke it" The nukes didn't fire (i had around 10 available atm). None of them. I tried dragging, shooting a single one, and changing targets. Nada. Is this known? Here's the game: http://www.pastats.com/chart?gameId=234584 I honestly don't know what happened with them. I was really mad. EDIT: i might not of had enough nukes anyway but that's not the point.
Nukes refuse to fire against a moving planet in recent builds. Got to launch them before the Halleys ignite. I've had cases where nukes refuse to launch against regular planets too, as well as orbital units and Halleys refusing to move. Sometimes the game just seems to fail to calculate an orbit.