I've seen this several times. I get a declaration of war from a civ, but no leader screen announcing it. I'm just at war. The grievances of the civ says I've declared war on their ally. Except that I'm not at war with their ally. It seems to happen when I've lost ally status with their ally. In this case, I was disliked by Georgia and Inca. I was allied with Japan. Japan went from ally back to liked, and I needed to renew the friendship and make them an ally. On that turn, Georgia and Inca both appeared as at war. Both had grievances on that turn because I declared war with their ally, Japan. But, I've never been at war with Japan. Wrong version in title. Corrected to 328.