(Bug) Get which documents are external Sharing via search working
Before December, when you shared with an external user with email address, it added the user as a person part of your Active Directory. Now when you share with an external user, a Sharing Link is created and the person signs in with a code.
It used to be that when a document was Shared externally, a managed property called "ViewableByExternalUsers=TRUE" it would bring back document shared externally. Since the new Sharing Links, this managed property doesn't seem to pick up that a document is shared externally.
Also on the https://[tenant].sharepoint.com//_layouts/15/siteanalytics.aspx?view=19 used to display any documents that was externally shared. It doesn't do this for document that share via a Sharing Link.
It's a bit hit and miss, as sometimes I can get the results back via Search if I have performed a re-index of the document library, but it's not every time.