I notice that if I sort the Network Flights list by Distance ascending, there's always 10-20 aircraft at the top of the list with Distance and Bearing BLANK. Even though they are listed with a valid Latitude/Longitude, and appear on the map.
Another bug to fix in the next version please.
http://www.flickr.com/photos/tarbat/5397336555/sizes/o/in/photostream/