Her KYT label told media outlets that Shinji's pharyngitis is so severe, she has trouble eating and speaking. They relayed, "She is currently receiving treatment and resting, and must halt all of her schedules for the time being. Koyote's comeback will also have to be pushed back." 

Recently, Shinji teased fans regarding Koyote's comeback with photos from the recording studio. However, it seems fans will have to wait a little longer to new music from the trio. 

Get well soon, Shinji.