You'll have to give a specific thread where you see this, all the ones I looked at show the online indicator out of position.
You have several issues with your style that you need to address:
As Brogan said, your message user info block has had its width increased. Due to this, avatars aren't centred in the block and the knock on is the misplaced online indicator (Also out of place on mobiles).
Your sign-up button needs looking at - the text overflows the button
Adverts don't fit properly in various views including on tablets and mobiles. You definitely need to sort this, especially if using AdSense.
If I am logged out, viewing as a guest then all avatars and the indicator seem OK. When I am logged in as admin it's my own and just one other I can see messed up (not an admin) All the others are good.
As a guest
Logged in as admin
AFAIK I haven't increased the message user info block, what width should it be.