What version of Opera are you running?
You do know that Opera did the same thing that Firefox did a few years back right, ie, they NO LONGER build their own browser engine and instead did like Firefox and use the Google Chrome engine and just add stuff on to that with the Opera name.
Opera 12.18 was the last x86 and x64 version of the original Presto browser engine. There's been NO security updates on either for about 2 or 3 years now and what you are seeing is the result of that with the security certificate thingie.
I know this because I still use the Old Presto engine Opera myself.