It was an issue for Coll/Viral where if you didn't have an infected/assimilated planet then sometimes the game would register your colony count as 0 when the empire goes to attack.

> What do you believe was the cause of it?
> > Hey,
> > 
> > We believe we've identified the bug causing the issue and have fixed it, so this shouldn't occur anymore. However if it does please take a SS and send it to me via Discord.
> > 
> > Thanks,
> > Raist
> > 
> > 
> > > ATTACKING
> > > 
> > > 
> > > Your empire has died please restart. (Options > Restart Empire)
> > > 
> > > That is the message that I saw when I clicked to attack an NPC