It is not irregular for information directly following a mass shooting to change. There’s often a massive response by law enforcement agencies, the scene officers arrive at is typically vast and chaotic, and investigations into how and why a mass killing happened often take weeks, if not months and years. That said, the misinformation spread by leaders in the aftermath of the Texas school shooting in Uvalde has been extensive and has drawn an abnormal amount of scrutiny. Read: https://www.kxan.com/news/texas/uvalde-school-shooting/a-timeline-of-misinformation-what-actually-happened-in-uvalde/