I've discovered that there appears to be missing tiles in two scale levels when you zoom in over Tucson, AZ. It appears that this occurs at the 4th and 5th scale levels if you make a map online. As best I can estimate these scales are approximately between about 1:24k to 1:7k. When using the web app, you'll see the "Map data not yet available", however in Arcmap, you'll see the lower scale images remain and become grainy. Above and below this scale range, the imagery appears to display normally. Is this issue to be resolved soon?