Same here, I have Competitor (complete 300 laps in multiplayer) stuck at 99% and logged into today to put some laps in. Still stuck. 
When I logged on it did, however, pop my Racecraft achievement which had been bugged for months, so that was a nice surprise.
Enthusiastic rival is still bugged for me, despite reaching the higher rival milestones for other achievements. Are these bugged achievements ever going to be fixed?
Bug Info:
Platform: Xbox Series X
Edition: Game Pass + Premium Add-Ons
Account: solo account, xbox id: Queue Jumper
PC GPU: N/A
Peripheral: N/A
Settings: Localization - English, Xbox region - US
Xbox Settings: no parental controls, not in Quick Resume
Attempted fixes: rebooted
Content Update: don’t know if it’s relevant
Attach one recent Livery reward message, I’ve got some livery reward before, enough to unlock the achievement:
Got this achievement yesterday on Series X
Maybe it pops after a race, at least that’s how it was for me
I have been playing Forza Motorsport since launch & still the technique achievement will not unlock & also the safety superstar achievement has stopped tracking even though I have met the requirements for it multiple times.
Just did another 1 lap race in the rain at night to see if my two achievements frozen at 98% would pop after downloading Update 7 and they’re STILL both at 98%, so this is STILL not fixed.
My progress towards the “Technique” achievement has been stuck at 99% since shortly after launch. I’ve been unable to unlock it despite earning a score of 9 or higher in many, many Track Segments since it reached 99%. See attached screenshot.
I submitted a support ticket (#551536) and the response I received was to remove and re-add my profile, which I did, but to no avail.
I saw that another player had the same issue and created a topic for it, but it was closed by support as they were unable to reproduce the issue. Instructions were to open a new topic and link to the existing one, which I will do.
Here is the link to the original topic: Achievements - Technique achievement not unlocking
I never used to find the Forza achievements to be bugged or broken… until this one.
My problem I believe was started by an online race crashing my game at the result screen. I was on four races with an ‘S’ safety rating and since then, no matter what I do, nothing allows me to unlock it.
This might never get unlocked, and I wonder if anyone else is going mad trying to fix it themselves?
Another 2 and a bit months, several more updates, and still nothing regarding fixing broken achievements. 7 months now that my safety superstar achievement remains locked at 90%. Somewhat reassuring to hear others are having similar issues but not keeping my hopes that they’ll look into this
Update 8 just dropped. Quelle surprise, no fix for broken achievements. Broken at launch and never fixed since, now 8 months later. Reporting issue/submitting tickets achieves nothing.
Thank goodness you introduced “updated track signage to maple valley” tho, don’t know how I would have coped without that 
So you’re saying I don’t need to launch this game and waste my time doing yet another lap at night while in the rain in an effort to get these achievements to pop? Thanks for saving me the trouble! Glad that my achievements have been stuck at 98% for over half a year now without even an acknowledgement of the issue! I’ll be sure to enjoy the increase track material luminance in the meantime!
I mean I can never guarantee as I’ve seen players before posting after previous updates that their respective achievement was fixed, but if I were to have a guess I’d say probably not! Mines the safety superstar one for 10 consecutive MP races at S rank, been stuck at 90% since first week of release.
Submitted tickets are always responded to by the same chat bots and nothing ever gets acknowledged.
Too right brother! So many updates for such minor details yet can’t get something that should be working from release fixed. Can’t even delete saved data and see if that would fix it 
Aficionado achievement bugged (need 10 lvl 50 car)… stopped tracking at 50% and didn’t unlock after 10th car 
garage royalty (need 30 lvl 50 car) also stopped tracking at 16%… looks bugged too.
pole position achievement also glitched after update 8
Anyone got a patch for the pole position achivment
after update8.0 this achievement no longer work on xbox series. pls fix it
Hello, i have the same issue than other ones, stucked at 99% of Technique achievement with a lot of 10 points segments done.
Please, give us a fix. Thanks!
Same here.
Still absolutely nothing following todays update, or even any acknowledgment. Thanks!
