I have just received the mission briefing for the final assault on the Lunatic Pandora from Laguna and co. at the Esthar Presidential Palace. As far as I can see from the numerous FAQs dotted around the internet, in order to progress the story I have to make contact using the Ragnarok with the Lunatic Pandora hovering over Tears Point on the world map. I have attempted to bash into the LP from just about every possible angle, but no cutscene or scene transition occurs.
That doesn't sound like your typical bug. Maybe you had talked to Laguna and then loaded a save from before the next time you played? (in other words, check if he is in the ragnarok)