When viewing a map in one of the Configurable Apps in ArcGIS.com online, the legend only displays the layers that are turned on initially. If you turn off layers or turn on additional layers, the legend does not update to reflect this. The legend appears to now be just a static legend of initial layers. It seems to occur on all "Configurable Apps", such as Basic Viewer, Compare Analysis, and Edit App, etc. It does NOT seem to occur on apps built with "Web AppBuilder". It would be preferable if these configurable apps had dynamic legends, too.