Commentaire officiel
The limit for the length of a flight is 30 km. If you flight is less than this there is likely something going on with where it is assuming you are taking off. If you are doing the layout and you have a long distance to get to the survey area this can eat it up pretty quickly.
Try putting a battery timer limit which will limit the amount of points that can be loaded in if you are currently set to unlimited flight duration.
Make sure your aircraft has a solid GPS fix and is showing the red triangle to show its current location. If it is not, sometimes it will default to 0 Lat and 0 Long which is a pretty long ways off unless you happen to be in a boat off the west coast of Africa.