Here mah boi, also I just had a theory what it could be.
There's an addon for Windows Explorer called "QtTabBar" which adds multiple tabs to Windows Explorer, the way it captures windows themselves though is through some ShellHook etc etc.
So maybe when Opera opens the file location, MBAM sees that the window is getting captured by QtTabBar's ShellHooking mechanism or something.
Haven't tested this on another machine thus far, but it's a possibility.
Also if the logs complain about modified windows files, that's me modding the crap out of them (which is why I try to avoid using fix tools, as it usually reverts things back), so don't worry there.