[selebrazin]

While the timing of the shutdown is indeed peculiar if not outright suspicious, I wonder if the "scheduled maintenance" part had something to do with the Emergency Directive 20-04 which was released by the Department of Homeland Security on September 18. It requires all federal agencies to apply a patch to mitigate the newest Windows vulnerability CVE-2020-1472, dubbed Zerologon.

Link: https://cyber.dhs.gov/ed/20-04/

From the article:

"Update all Windows Servers with the domain controller role by 11:59 PM EDT, Monday, September 21, 2020,

Apply the August 2020 Security Update to all Windows Servers with the domain controller role. If affected domain controllers cannot be updated, ensure they are removed from the network."