The edit form caption that gets duplicated from the insert item to the edited items is an issue our developers will investigate. You can track this issue through the Public Issue Tracking System (PITS) logging to telerik.com with your Client.NET account.
As for the edit form and insert form showing together, this is the expected behavior in RadGrid. Particularly, the insert form visibility is not affected by other edit forms visible on page. If you need to synchronize them, meaning only either a single insert form or an edit form is open at a time, you can use RadGrid's ItemCommand
sender, GridCommandEventArgs e)
(e.CommandName == RadGrid.InitInsertCommandName)
(e.CommandName == RadGrid.EditCommandName && e.Item.OwnerTableView.IsItemInserted)
the Telerik team