error in the shoulders (Patreon)

I should have posted this model yesterday, but I realized it has a major flaw in the shoulders. For some reason, it's deformed like this, and the worst part is I can't find the problem. I've checked the paint weight and the bones, and everything seems fine, but I still have this bad deformation. Rebuilding it from scratch is unacceptable. I've spent almost four days on this model, only to have to throw it away for this. I don't know what to do.