I think I'm having this same issue where I launch mission 8 and it's just like freeflight mode with wingmen, there's no dialog or anything. I'm using the Steam version and I've tried switching from openbeta to stable, and it seems to be the same. Is there anything I can try to fix this?
edit - nevermind, I got it. I had copied the mission files from the DCS steam folder to my users' Saved Games folder so I could load them, so they were out of date. Copying again with the updated files made it work like a champ