Can't see the track on the map even though I was live tracking and it also apepared in the TRACKS list complete with stats.

Hi there.  Yesterday I was out hiking and recording my track.  I checked several times during the day and it was going fine with a pink line showing my track.  After lunch, for some, reason the pink line of my track had disappeared from my map.  I went back to the database and found that the track stats were still there so BCN clearly knows about the track but I couldn't actually see it.  So, I tried to change the colour of the track and changed it to blue to see if it would 'reappear' but no joy.  I eventually got it back but had to export it then import it back to get it to show on the map.  I must have done something wrong but just not sure.  Any clues?