Whenever I load a save game, people in may party except for my main character become less dark. This only happens to the ones in my party and not the ones left back at the ship. Thus, if a person like atton gets dark mastery, and i save it, he wont have it anymore when i load. He'll only be mostly dark. Is this a known bug or is there some way to fix this?

this is a minor bug, i think. either way, i wouldn't worry about it too much: the influence system will automatically make him fully dark once you reach 70+ influence with that character once you have them in your party.

hope that helps. :)