On March 19, 2026, the official RIIZE Instagram celebrated member Eunseok’s birthday with a post that’s already going viral. In the photos, Eunseok beams while holding two tres leches cakes, alongside the message "FELIZ CUMPLEAÑOS A LOS QUE CUMPLEN EN MARZO." Fans quickly flooded the comments with birthday wishes, including messages like, "Eunseok, why are you so cute lol—happy birthday! We even share the same birthday."