Until Papyrus Oxygen.3, the created NamedElement were automatically named. The name was found according to the element's UML Metaclass, suffixed by an index. This index was found crossing all the elements in the owner until to build a unique name ( Metaclass' name + index). This strategy cost many time for huge model and most of the time, the found name is replaced by the user just after the element's creation.
Since Papyrus Oxygen.3, we implement new strategies, to reduce the time consumption.
Papyrus uses the quick index strategy by default.
A preference has been created to allow to the user to choose the naming. To change it, go into
Window > Preferences > Papyrus > UML Naming Strategy.