https://www.bleepingcomputer.com/news/microsoft/windows-10-alert-defragger-bug-defrags-ssd-drives-too-often/

With the release of Windows 10 version 2004, the Windows Defragger has become a mess as it starts to defrag SSD drives too often, perform trim on non-SSD drives, and forgets when it last optimized a drive.

Windows 10 includes an 'Automatic Maintenance' feature under Control Panel ->  System and Security -> Security and Maintenance that performs various maintenance tasks on a scheduled basis. This maintenance includes checking drives to see if they need to be optimized (defragged/trimmed), checking for new updates, security scanning, and other diagnostics.