On Xbox.com my GS is 86809 but on my Console its 87014, i remember tweeting the support about it but helpfull they were not, iv given up on it being sorted, its not a massive issue but its nice when things are correct.
It's not just an issue between my Xbox and the forums, when I'm sitting on the main dashboard it shows the wrong score but when I actually go into my achievements it shows the correct score, same for a few of my mates.
Also when I click on my mates Gamertag it shows the wrong score but if I 'Compare Achievements' with him it shows the correct score, this is all from the Xbox 360 Dashboard aswell.
I haven't noticed any issues with my Gamerscore between Xbox.com and my 360, but an issue wouldn't be too surprising. There's a fair chance that Microsoft has some kind of issue between the services at the moment. Like everyone else I'm hoping any issue
will be sorted out as soon as possible.