Achievements earned on xbox 360 console not showing on Xbox one

Here is the support page for this issue.
http://support.xbox.com/en-US/games/troubleshooting/troubleshoot-achievements-challenges You can scroll down and try each solution to solve this issue.

Hey, BlHimmel! We are aware of a situation where some achievements do not unlock on the Xbox One console. This shows up as either Xbox One achievements not unlocking, Xbox 360 achievements not unlocking, or both not unlocking.

We are working on resolving this right now, however the current workaround is to do a

factory reset on your console. Give that a shot following the steps there; you can keep your games and apps. After that, try to earn an easy achievement for an Xbox 360 game, and let us know how it goes!

As long as you log into the Xbox 360 using the same accounts as you do on the Xbox One, then yes, any achievement you earn on the 360 will count towards your account and show up on the Xbox One

Hope this helps and enjoy gaming on!

After looking into it, a temporary fix is apparently earning achievement on 360, which I did and now it's back to my intended gamerscore of 190206, but if I go back onto my Xbox one and earn an achievement it will revert back to what it's glitched at. So
it's apparently Xbox one that causes it to mess up on all sites. So right now my gamerscore shows as 190206, which it's supposed to be but it will revert back to 189726 or 189761 depending on how it feels. The 360 achievement is not a permanent solution if
you play on Xbox one but it will show you what your gamerscore is supposed to be at!

Hey there, Brain is ToaSty! This is definitely an odd one, and I hope that we can get some answers here.

Since your profile is set to private, I can't see your achievements. However, both FIFA 14 and Madden 25 are on the Xbox 360. I'm wondering if you might have earned these achievements on your 360 if you own them there? This would explain the achievements
popping on the Xbox One, because they sync like that for some games.

Achievements disappearing on the Xbox 360 for Xbox One titles is a known issue. To resolve that, simply earn another achievement on your Xbox 360. This will correctly recalculate your gamerscore and show the Xbox One achievements in there. While on the 360,
you cannot see your Xbox One achievements individually.

And lastly, if you added those friends on the Xbox One, you will not see them show up on your Xbox 360. That is because there is a different system for adding friends on the Xbox One that makes it so you cannot see them on your Xbox 360. If you add them
on your 360 or xbox.com, they will need to approve you via another 360 or xbox.com for them to show up on your account on your 360.

Phew. Man, that's a lot of information. I hope it helped clear some things up for you! Please do post back if you have further questions on any of these situations!