This created a bad situation for two reasons. First, it was extremely exploitable. Two, someone could get stuck where they couldn't progress because of their Mission not completing. For this reason we brought the servers down and started exploring if we could fix it live, without a patch (we can!).
We believe we can get this issue resolved and get the servers back online within about 45 minutes from the time of my post (hopefully sooner!). I will continue to pass on updates as I have them, thanks everyone.
-eric