Breaking a Design Line which doesn't have placed node components does not result in these "extra" nodes. It is only when a placed node component is added that the problems begin.
My procedure is to select the Design Line with the placed node components to break, Fill in 3D and then delete the design line. Next, use the Revdesign command to rebuild the Design Line and erase 3D items leaving the "new" Design Line. Now when you break the design line, the original placed nodes will be highlighted but will not populate. Those nodes can be eliminated by using the revdesign command on each of the new design lines created.