Software patches for servers are usually intended to fix critical issues, but the recent round is instead causing them. So much so that Microsoft has decided to pull the January 2022 Patch Tuesday updates for Windows Server (via Bleeping Computer.)
There are three specific updates that Microsoft pulled depending on which version of Windows Server you're running. KB5009624 is for Windows Server 2012, KB5009557 is for Windows Server 2019, and KB5009555 is for Windows Server 2022. According to various social media reports, on all these versions the updates in question can cause domain controllers to fail, servers to reboot every few minutes, Hyper-V not to start, and ReFS file systems to become inaccessible.
Microsoft appears to be aware of these issues, and in the changelogs for most of these Windows Server updates, indicate that "we are working on a resolution and will provide an update in an upcoming release." Even with that so, Bleeping Computer notes that not every system administrator can verify that these problematic updates are no longer available for download. As a workaround, admins can pause updates to avoid having it automatically downloaded.