UML14 — Inconsistent attachment of Activity Diagram

Summary: p. 121 NG "The entire activity diagram is attached (through the model) to a
class or to the implementation of an operation or a use case."

• How can an activity diagram be attached to THE IMPLEMENTATION of
  an operation or use case?
• This attachement is different from the one in the SG, p.124:
  "[1] An ActivityModel specifies the dynamics of a
  Package, or (ii) a Classifier (including UseCase), or (iii) a
  BehavioralFeature."

Considered and declined.