Windows 10 includes two disk cleanup features that allow users to free up storage space used by unnecessary system and temporary files. Microsoft is making changes to these features to prevent Windows users from deleting files in the Downloads folder by accident. Microsoft has also been steadily improving a modern version of the Disk Cleanup tool as a new integrated feature called Storage Sense. Today’s release of the Windows 10 Insider build 19640, Microsoft is changing this functionality by not clearing unused Downloads if the folder is synced to a cloud provider.
Source: https://www.bleepingcomputer.com/news/microsoft/windows-10-tweaked-to-prevent-accidental-file-deletion/