After users encountered a raft of issues, Apple appears to have pulled the latest macOS Mojave Security Update, as well as the Safari 14 download for macOS Mojave.
Mike Peterson for AppleInsider:
According to Mr. Macintosh, some of the issues that users experienced include problems with memory, slow boot and high fan speeds, system sluggishness, and stalls in Finder, among other problems. Apple pulled both updates at around 5 p.m. Eastern on Sept. 30.
Complaints about the update started to surface shortly after it was released on Sept. 24, though the Safari 14 update for Mojave was released on Sept. 16. The exact update for macOS Mojave was Security Update 2020-005.
MacDailyNews Take: If you meet the hardware requirements and your software is compatible, users on macOS Mojave should upgrade to macOS Catalina.