On a SysML Requirements Diagram you can create a Requirement (e.g. Req1) and add two items (e.g. Class1 and Class1) with a satisfy link from Class1 to Req1. If you then move the link (source) from Class1 to Class2 and look in the Relationships Browser for Req1 then the satisfy link has moved from Class 1 to Class 2 as expected. However, if you repeat this on a Class Diagram the diagram shows the new link being moved but the Relationships Browser still shows the satisfy link to Class1. The behaviour on the Class Diagram should be the same as the Requirements Diagram.