I just completed the halo ODST mission Uplift Reserve with a score much larger than the par. However the achievement did not pop and the score hasn’t been recorded. It would be great to know if a solution is available so I can deal with this problem. I do have a screenshot of the score but I don’t know how to post an image in this text box.
I had the same issue, beat the par score on The Ark on Halo 3 (MCC) with a score of 34,775 which was much larger than the 25,000 required par score, yet the achievement did not unlock for me and the score has not been recorded in Halo Waypoint. Hoping for a solution to this issue within the Master Chief Collection, along with other issues.
Try running through it again on Easy. Might “push” your prior results through.