Mission Menu and Security Clearance blank.

Sometimes when I reload game the security level has gone back zero and there's no missions listed in the menu. Restarting fixes it but if you don't notice and continue it bugs out the story. Think it could explain the various story breaking bugs that have happened. Still a fantastic game though. I now use my saves very carefully so I can restart if there's any problem. Always save at the start of a Chapter and create new saves for progress during the chapter. That way you've always got a nearby save and don't have to go right back to beginning...