Those NPC ships with a blue visible shield in front of them can ram player outside the map, eg behind a mountain or inside an obstacle.
There is only one way to return after that, self destruct and duplicate.
Happened to me a few times now, in average once within 2-3 weeks.
I can not find a bug report section for maps, thus i am sorry if there is one, otherwise i am requesting the creation of a subsection for map structures etc.
