We just ran a level 19 fractal and the 3rd one we got was the Thaumanova it was pretty straight forward, after we took down final boss, the cut sence did not play, everyone just stayed up top, 3 ppl who where down had the retry from checkpoint and it put them back in the starting room, the other 2 where just left on the upper platform, where it continued to randomly remove tiles on the floor as if the boss fight was still active,
No one got the final chest, but we all had the option to continue to the final fractal….