When you copy data between Sharepoint sites, metadata is lost (e.g. the created by, modified by fields).
Here’s a quick bit of PowerShell that will ‘sync’ those values from Sharepoint location A to Sharepoint location B for you!
https://github.com/jflieben/assortedFunctionsV2/tree/main/SpOtoSpO
[…] Copying Sharepoint Metadata […]