Ok i am playing multplayer game with 1 AI and due to lack of others just me in it.
NP more planets to claim for me.
However i claimed a planet 3 turns ago. But just noticed that my lost defender cant reach it because it is out of travel range...
Aka that planet didnt add to my travel range. The lost defender has been selected as idle ship for those turns.
edit: 2 turns later i selected an other ship and it updated. So now all ships can travel as intended