If I use an ArcGISDynamicMapServiceLayer as a basemap in the basemap gallery and then I change the from that basemap to an ESRI basemap like world imagery the map goes blank and world imagery never loads. Could this be caused by the first layer into the map ,the ArcGISDynamicMapServiceLayer layer, did not initializing the map's LOD? The spatial reference in the ArcGISDynamicMapServiceLayer is web mercator. I'd post an example, but most project is very complex. An ideas?