Dude was buzzed with the very first shot that landed, one has to question has he been hiding china with his shyt work rate , maybe he 's afraid to let his hands go because he knows his chin is brittle.....I will have to respectfully say I dont have much of an issue with Broner's chin. He was taking shots from a puncher at a weight he hasnt fully saturated in at yet. One reason he didnt react well in the beginning is because he was dry. Also, he was moving backwards with his hands down and his chin up. Once he warmed up he took the shots better. In the 8th round, he just got caught squared up. While he shouldnt make a habit of taking shots, I see his main issue with his KDs as being poor defense. He defense in that fight was amateurish as hell. He basically fights like that all the time but his bad habits cost him against a guy who could make him pay for those bad habits. So I am much more concerned with his technical flaws than his chin.
Who knows Errol Spence truly ko'ed him in sparring, regardless his chin is suspect