There has been deliberately sand-bagging of Opera documented with MSN. They were sending style sheets that screwed with Opera's page layout so that people would think Opera had bugs. The response to this was the (in)famous 'bork-edition' of Opera.
http://www.opera.com/pressreleases/en/2003/02/14/
SO it's not impossible that MS is 'doing it again' although they are risking another lawsuit if so. Opera settled for several millions in a settlement rather than pursue the first one to the bitter end. If they are forced to sue again they could be ticked-off enough to force the issue this time.
One way to test this would be to alter your user-agent string. The authors of Opera have provided the means to do this in the browser itself because of their status as a 'small player' in the world of big sharks.
http://www.opera.com/support/search/....dml?index=570
You can try substituting an IE user-agent string and see if it solves your problems.