The last three games I have attempted to play have resulted in this issue. Once the quest goes live to locate and occupy a majority of the loadstone systems. The loadstone systems ping on the galaxy map like they should but the systems themselves are invisible and can't be selected to send your troops there. But the computer can send troops and occupy the systems. Even if they are occupied by the opposing faction you can't select the system and therefore you are unable to compete or complete the quest. I am not sure how or why it happens but thus far I can't find a way to fix it. Here is a screen shot of the issue I am unsure how to provide the save game files..

Send probes to uncover the systems, first. You only can travel to systems, what you had view on.

Yep, select your explorer class ship or hero ship with probes. Send as close to the area in question. then in operations select manual probe. then launch in that direction.