In short, the bug occurs at the end of the mission Hot Rod, Chapter 08. When completing and extracting from the mission, with all objectives complete and all optionals complete as well, the game acts as if the mission is not completed. No victory screen, no defeat screen, it simply sends you back to the basic story menu with no choice but to start the mission over again. Recreating the bug seems pointless, given that I would either complete the mission successfully and no longer be concerned, or waste another hour trying. One of my main drawbacks of this game is the extensive time requirement necessary to truly play it, and that is not helped in any way shape or form by the game not acknowledging completed missions.