Just happend like 20minutes ago. It was a random BG against a russian team with 3 rogues.
First we wiped them at the fight at WW when battle starts, got the flag when it was done. Then we lost the flag with 2 guys defending it to a russian rogue.
Ok, team went back and re-capped it. Lost the flag again after 2 minutes to the same rogue. I was there at WW, fighting so I thought I missed the cap.
We re-re-capped the flag for the 3rd time. I was standing 10 yards away from the flag, watching it like a hawk with another 3 guys from my team, doing nothing since we won the fight.
Then the message appears: "Cykablyet(Rogue) has defended Waterworks!"
How he did it, I'm not exactly sure. Since they where 3 Rogues, I got a feeling they used shroud of concealment on eachother when he capped the base, since I randomly used whirlwind once and knocked one of them out of stealth close to the flag. Guy under in red was the one who capped all 3 times.