I would like to know why only some of the missions completed are recorded on the leaderboards and others are not. I have had to replay several missions in Halo CE to get their times to count towards the “legendary under 3 hours” achievement and have encountered the same issue in Halo 2. Note that I was online during all of these times. I also didn’t unlock the par time achievements for missions that didn’t get recorded on the leaderboards. Any way to fix this?
I have not experienced this issue myself but I know many others have - hopefully they put some time into fixing issues with the campaign since it hasn’t really been touched yet compared to multiplayer. In the meantime, I’ve heard that saving and quitting in the middle of a mission sometimes causes issues with campaign progress and par times, but if you’re going for the 3 hour achievements this is probably unavoidable, so hopefully this will be fixed in a coming update.