I agree with Frog that "edge cases" shouldn't affect game reviews (and in my case, they won't), but the FOW bug isn't that much of an edge case. I've seen it over a half-dozen times and for someone like me, the bug is a current-play-through killer. The exploration phase is so important -and so fun - that the elimination of it 1, 2, 3 and sometimes 4 or 5 hours in to a game makes me very tempted to give up that play through.
It has occurred in half my games and I have sent those saves in (and will send the latest one in, too). For a game that gets SO MUCH right, leaving some of these potential bugs in seems a disservice to the hard work of everyone and frankly, disappoints me.
Still love you guys, though.