As I could see, the poblem here is with a serialized property of RadTabStrip or has been manually modified in the designer.cs of your form. Please try to delete that line and then try again. We haven't made any changes with the TabScrollButonPosition
property for the SP2
and that behavior is pretty strange.
If it is appropriate you could open a new support ticket and send us a sample project which is replicating that fault behavior and we will try to fix it for you.
the Telerik team