Winter, a member of the group aespa, was absent from a concert due to flu symptoms. Winter was scheduled to attend the '2025 aespa LIVE TOUR - SYNK : aeXIS LINE' performance held in Bangkok, Thailand, between November 15 and 16, but was unable to perform on the 16th. On the 16th, SM Entertainment announced through their official SNS, "Winter visited the hospital after the performance on the 15th and was diagnosed with cold and flu-like symptoms," adding, "Following the doctor's recommendation to get sufficient rest, she cannot attend the concert."

The agency stated, "This decision was made with the artist's health and safety as the top priority," and added, "We ask for the understanding of all fans." Despite Winter's absence, aespa performed as scheduled with the other three members. aespa returned to Korea on the morning of November 17 through Incheon International Airport, and it is known that Winter is currently focusing on rest and recovery.

aespa celebrated their 5th anniversary on November 17. Debuting on November 17, 2020, aespa made a strong impression with "Black Mamba" and has since released numerous hit songs including "Next Level," "Savage," "Supernova," "Armageddon," "Whiplash," and "Rich Man." To commemorate their 5th anniversary, aespa released 'aespa 2025 Special Digital Single - SYNK: aeXIS LINE,' featuring solo tracks by each member. This digital single includes solo songs by Karina, Winter, Giselle, and Ningning, which were showcased at aespa's third solo concert.

Although Winter's absence was disappointing, aespa expressed their gratitude to fans by holding a cake to celebrate the 5th anniversary. aespa's official social media accounts showed the members enjoying the party, with Winter wearing a thick coat and mask indoors, evoking sympathy from fans.

Currently, aespa is conducting the '2025 aespa LIVE TOUR - SYNK : aeXIS LINE.' This tour is gaining great popularity both domestically and internationally, and aespa plans to continue various activities in the future.