Hey,
i just played fractal of the mist with a pug. It was a pretty normal run. At jade maw fractal after killing the first 2 tentacles, a random suddenly told us only to kill colossus, not the tentacles (but we already killed one) and not to use the crystals (but i think someone already used one).
the random stood directly below the boss near the spot you would use to kill the rear tentacle in the beginning and he did something maybe, dont know.
After killing the last colossus, we all suddenly got the skull and the boss was down.
So there exist an exploit you can use to kill the jade maw after killing the colossus. Please look into it.
Thank you.