https://www.bleepingcomputer.com/news/microsoft/microsoft-halts-rollout-of-windows-10-kb5001649-emergency-update/

Microsoft has paused the Windows 10 KB5001649 cumulative update rollout, likely due to installation issues and reported crashes. Microsoft is now offering the previously released KB5001567 emergency update instead.

The March 2021 updates have been a complete mess when printing, with update after update causing new issues to arise.