|You've created a List View and shared it solely to All Partner Users. However, a few Internal Users can still access the List View. Under unique scenarios, a User may be the manager of a Partner User that is in turn a member of a Partner Group. In these scenarios, the Internal User (Manager) is also considered a member of the Partner Group. This membership inclusion marks the Internal User (Manager) as being a Partner. They aren't actually changed to a Partner User but rather have the Partner User indicator for visibility. Therefore, they will be able to view things shared solely to Partner Users.