Either IE dropped by 15% overnight, last September (with Opera taking those 15%), or SC figured a way around Opera's IE cloaking. Or maybe a new version of Opera came out that had Opera set by default as its UA string? Anyone know?
Opera has several different levels of cloaking, and it can really through a UA parser for a loop.
Opera can declare itself solely as Opera, or as IE but still mention that it is Opera, or as Firefox but still mention it is Opera, or as IE or Firefox without mentioning it is Opera, or whatever the user wants to type in there to be clever.
At least after 2009 01 01