Invasion game mode finished it but no ticket

After several hours, my friends and i managed to complete the onslaught game mode. Post game none of us got a ticket. Now, im hoping this is a bug or something, because we put a lot of effort into the mode and finished a mission. I also hope that its not a rng when a ticket drops, because that will piss people that finish the mode but got no tickets like what happen to my group.