Not sure how long it has been like this but I noticed it, and now my OCD is acting up.

I am not sure how long it has been acting like that for, but i noticed it acting like that for probably a couple of weeks now. But somebody mentioned that i should turn off the Donate/Give points function so i did and it is now correctly adding up the number of points now. But i have had that on for a multitude of months and it had never done that until very recently now. So it looks like it is fixed but the number of points shown in both the Game Pass app and my Microsoft Rewards page still have different numbers for my total points, with one saying i can redeem them and the other saying i am still short some.

How long has the site been acting up, if you know?

How long has this been happening? did it just start today? My guess is the ISP acting up. Is your PC running slow by any chance? Also, how old is your Xbox 360? I know it's an old version, but how long have you owned it and played on it?

If it's a really old machine that's been used for years, it could be on its last legs.

Being in the Preview Program is exactly why your Xbox is acting weird. The preview program is essentially beta-testing for the next firmware release, and bugs are to be expected and reported.

You should have access to a private forum for Preview Program members. They can offer you more specialized help.

If you want to remove yourself from the Preview Program, you can read more here:

http://support.xbox.com/en-US/xbox-one/console/xbox-update-preview-faq

This happened to me as well, less than a week ago. How long has this been happening for you? I noticed all day one day that my Gamerscore was not going up, but after I closed the Xbox out that night and then went back on it the next day, I looked and it
had gone up and is now working correctly.