What I noticed about Rushdown is that it doesn't immediately count as completed when you load in to the rewards zone. It takes around a full minute (prolly to give some time to ppl to look at their loot, or maybe different dev reason). So it counts around or just before the moment you see the screen with the results and give commendations. Did you guys waited for that to happen? Because if you left early maybe that's the reason. Else I don't know what to say... maybe it's a nasty bug.