User blog comment:Damac1214/Back in Black - Call of Duty: Black Ops III teased, reveal trailer coming April 26th/@comment-3171236-20150410061314/@comment-1916935-20150410193354

Well, according to the timeline on the wiki, Charybdis took place in October of '78 and Mason did an operation for the CIA in July of '79, so Charydbis could've still happened, but the events resolved fairly quickly. It could explain why Weaver didn't return.