MCC: PC - Reach. Nightfall not registering time

So i have a few achievements that are bugged like others but they seem to be the ones nobody else has. I believe i have had this pinned down to a syncing or registering issue that the game simply does not recognize i have done them.
The one thats frustrating me the most is that i cannot get the Pedrogas achievement because it is not recognizing my Nightfall speedrun time.
I have done this with and without the forklift cheese to verify. both in and out of a playlist and standard campaign, on LASO, no skulls all 10 scoring skulls etc etc. I verified this as i beat my current Winter and ONI times by a few minutes and my best legendary campaign time updated accordingly but when i beat my Nightfall run by 20 sec (4:03 down to 3:43) the time didnt update and is stuck at 3:47:45.
By my calculations from the times i pulled from post level screen i should be at least 5min under the 3 hour mark from memory.
I have created a support ticket but this has been ignored for a few weeks after the generic ‘we need dxdiag please’ copypasta was posted.
I have done everything i can think of to deleting local files, uninstalling and redownloading/installing the game, unlinking and relinking microsoft account etc etc.
This may or may not be related to the other achievements that are bugged as they too are not registering as completed, the main 2 offenders being collection eligibility, jorge cant have all the big guns and easy to overlook despite me having dozens of attempts under various circumstances trying to unlock them. These have also been months ago now so i believe im past the sometimes wait it out till it pops next login phase some people have.
I also try these achievements a few times a week to make sure they havent been patched or unbugged themselves since.
Has anyone experienced this kind of issue before? Kinda bummed 343 are ignoring tickets but it is what it is.
Here is a link to the ticket as there may be more info there i have forgotten to write here plus screenshots of my issues.
https://support.halowaypoint.com/hc/en-us/requests/21342
TIA

Is this on Xbox? One suggestion I have is to try and clear the cache by going to your Blu-Ray settings and clearing persistent storage. Then, try and do a hard reset. Once your Xbox is on again, clear persistent storage again. Then try the speedrun.

I’m glad you mentioned the “dxdiag” thing. I have a ticket open for HW2 for Xbox and “Support” has been saying the same thing to me over and over as well. They seem totally uninformed on the games they are dealing with and come across as severely incompetent. Shame that the people who get paid to fix games have no clue, but we as gamers have more of an idea of how to troubleshoot and often fix issues that should never have been there.

No this is on PC
Have tried the cache/save/file delete on PC with no luck