"Contrary to some reports, the former Lille player has not fractured his shoulder, but will have to go under the knife to fix the problem which is understood to be an historic injury."
https://www.skysports.com/football/news/13961/11733715/brighton-and-malis-yves-bissouma-to-miss-2019-africa-cup-of-nations
That's odd I heard it was a fractured shoulder and he'd be out for 8-12 weeks.