Again.
Every patch in WoW’s history has launched with bugs. Every single one. I know because I’ve been playing this game for 20 years; I’ve been here for every major and minor patch launch, including the many vanilla patches that had labels like 1.0.10c because the 10c patch had to fix a bug introduced by the 10b patch.
You could put every patch through a year of QA testing and you’d still have bugs drop on launch.