Take a look at the current page in Opera (version 10.53):
In Any Browser Except Opera 10.53:
Two rows of links that appear as squares with borders because of some CSS styling. This is the correct look; no bug.
In Opera 10.53:
The first link on the page does not appear to have any styling and its text is visible — until you mouse over it, and then the problem is fixed. If you refresh the page, the problem comes back. You also might see the text appear on the other links when you mouse over them immediately after a page refresh (although this only seemed to happen for me locally).