SM Entertainment sought to clear the air regarding the controversy currently surrounding f(x) member Sulli.

On September 23, f(x)'s agency SM Entertainment stated, "We believe Sulli hasn't been feeling her best, and that's why she missed her timing for that particular part of the choreography."

Sulli's attitude controversy started last weekend, when the online community commented on a YouTube video, a fancam video of f(x)'s "Rum Pum Pum Pum" performance, from the "Korea Night" stage at the World Federation of Neurosurgical Societies Conference in Seoul on September 11.

Sulli didn't do the dance move in which the members get on the floor, do the splits, lie on their sides, then get up from the floor. Instead, she squatted down, held onto the hem of her skirt, and sat there while the other members danced.

Netizens commented on Sulli's performance and said, "Even though the event wasn't broadcast, Sulli shouldn't have been so half-hearted." While some suggested that perhaps her skirt was too short, others commented, "Her skirt is the same length as everyone else's, but she was the only one who didn't do the dance." Still, others were willing to give her the benefit of the doubt and worried, "It could be that she isn't feeling too well," due to her recent diet and weight loss.