Not talking about the ones listed as not working in the known bugs sticky thread, but the other two.
If I search for everything, my mission doesn't show up. If I search by name, it does. If I go to custom search and set it to a minimum of two stars, it will show me three missions, not including mine. If I then set it to search for my name, as well as a min of two stars, mine shows up.
The minimum setting is also still bugged. A search for three star rated missions will not show three star rated missions, just ones with an average higher than three.
This incomplete list means that only a few people's missions get tested.
Additionally, the current ratings shown on newer missions are messed up. It is dividing by five rather than the number of people who have rated the mission. As a result, a mission with a single rating of five stars will show as one star, but a mission with 25 one star ratings will show as averaging five stars. These messed up ratings also impact the search by minimum number of stars.
So any mission that's been played more will tend to be rated higher and therefore played even more, while a new mission will have a poor average.