While in a chat room and you hover over my photo and click on 'user profile on stackoverflow.com' it will go to this URL (404):
https://stackoverflow.com/users/5207687/clayton
Here is my chat profile:
https://chat.stackoverflow.com/users/5207687/clayton
My chat profile also displays the wrong reputation and badges for my SO profile.
I suspect it's related to recently merging my account with a Gmail account.
If the accounts are not synchronized correctly perhaps it should simply not display the link instead of having a broken link.