ANY coaching hire has to be veted, and approved by the bretheren... That process takes time.  LSU new about it early, and the word got out.  BYU made it's decision, but can't make a public annoucment about the hire until they have formal approval.  By the very nature of the process, it takes time.  ANY and ALL major changes with BYU coaching changes are likely going to be reported by other outlets before BYU makes a formal annoucement.