WotC has vast files on what takes place in books, modules, source books, boxed sets, etc... It is unmanageably large, and they do not provide it to everyone writing for the Forgotten Realms or other settings. As a result, there is a lot of inconsistency.
However, this does not matter much to most DMs and players as their versions of the Forgotten Realms diverge from the source books in meaningful ways. My version of the Realms began in 1988 and never featured a Time of Troubles or Spellplague. 65 years in game time have taken place since those first adventures in Cormyr, and my FR is so different from the published FR that anything I'd take from newly relased product needs to be massively modified to work in my setting. For example, my Waterdeep was destroyed entirely before 1990 by the Cult of the Dragon and a 300 Foot Dracolich. As such, Dragonheist would not really work for my setting.