If a file has been linked to the Board outline layer, then an attempt will be made to automatically define the outer and inner (if any) contour objects. The auto-contour operation is performed after autolinking, or when switching to the Outline pane (if the outer contour is not yet defined).
Auto-contour does not work properly in all cases. Therefore, the outline should always be checked before publishing the imported product. In particular, automatically generated outline objects will have the default tool diameter specified with the Configure|Options menu command. If this is too large, then the objects must be deleted and re-created manually.
Auto-outline may be disabled by selecting the Configure|Automatic outline enabled menu item.