Hi @john john Pter,
This is an expected behavior in SharePoint. After you click "Send" button in the Share window, the group will have direct access to the folder and people in this group will receive an email which says the folder has been shared with them. You can see the sharing link by click "Manage access" >> Links.
These links will expire after the expiration date you set. You will no longer see the links in this window, and you will not be able to copy and share them.
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