Is it possible to know that the user has started "Save & Publish" when you look at the ContentSavingNotification? Lets say you want to change a property only if the content-node is going to be published right after it is saved.

For context, could you tell a bit more about what you are trying to do? Why do you only need to update a property on publish?

@Luuk Peters (ProudNerds) one example could be replace all external links with shorturls. And that should only happen just before publish of the page. If it is only [Save], then the editors still have the option to edit the original link-url.