There is a scenario where the bug was possible on test, but no one noticed it because the number of chances for it to happen are too small. If, as an example, you are on 5/6 and drop off, let's say for a PvP match, and that despawns the patrol it might drop the number of patrols from 7 to 6. If you are on test one group gone won't likely be noticed by the players testing. They just find the next group unaware of the number that should be up.
Go to live and a bunch of people go to dungeons, PvP, drop connection, etc and then the problem is obvious. I'm not saying that's what happend, but it's a way that the problem can exist on test, but not be apparent.