I don't see why this would not work, since the video clearly shows how the menu item is correctly rendered. Can you try with this code
<telerik:RadMenu runat="server" ID="RadMenu1" DataSourceID="SitefinitySiteMapDataSource1"></telerik:RadMenu>
<sfMap:SitefinitySiteMapDataSource runat="server" ID="SitefinitySiteMapDataSource1" ShowStartingNode="false" />
If the problem persists the problem seems to be related to the upgrade you performed. If you add the same logic as mine to another application do you get the same issues?
All the best,
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items