The reason why it's usually bugged at lower levels is because there aren't a lot of participants. At higher levels, it's rarely bugged. Maybe 1 out of every 15 games. but I noticed at peak hours, it always works... It only bugs for me at slow hours.
Basically, once you register, you are placed in a room with people around your level range. You kill the mobs that spawn with you. One of them has a key, and once you grab the key, you are allowed to move into the hallway. The whole goal is to take the flag and kill the opposing team. It lasts for 20 min, and the winner is decided by who has the flag on their pole at the end.
You have to rely on several other players though. Sometimes, this can be very frustrating, especially if you have a team that does not want to work together. You'll have people going invisible or stealth, which is also very annoying sometimes. It's a good idea to invest in detectors if you're a CTF junkie like me. You'll also be spawn camped sometimes. The way JM has the arena set up does not work for the players advantage. There are going to be a lot of times where as soon as you spawn in, the other team will kill you. Doing this doesn't allow you to buff or move to safety, and it's frustrating sometimes. But if your team works together, this can be easily turned around. Trust me, it's happened to me a lot.
But CTF is a very fun game. The rewards from turning in the tickets aren't really that good, but not a lot of people play for tickets. Some people play for the EXP from the mobs then return scroll. At lower levels, I used to get 10-20% for killing off all the mobs in the room.

CTF