Changing the name of the report (or any work item) through the Name
property in the Property Grid actually changes the component's site name, which results in changing the identifier of the corresponding class member (for each component/item on the design surface there is a member field generated automatically from the VS designer). You can observe similar behavior within a Windows Forms form, for example. This is the default Visual Studio designer behavior and is not possible to be changed.
I am sorry for not being able to help you.
the Telerik team