Digital cameras are truly amazing devices. Unfortunately all of them produce artifacts whenever extreme over exposure is present. Some lens/sensor combinations perform differently than others. I have seen smaller, similar and worse artifacts with my LUMIX G1, D200, 300 and 700 bodies. The artifacts are highly situational. You can find thousands of photographs from every make of digital camera with similar and worse artifacts on Flickr.
The X100 lens does seem to present flare at F 2. The flare seems to reduce as it's stopped down. But the X100 is like all other digital cameras, it doe not perform well when extreme over exposure is present. More attention to exposure will minimize the flaws in the X100 sensor/lens combination, but this is always the case.