I don't think that those bright spots are flaw of corona. In real life you would get the same. But due to imperfections of optical elements, be it pupil or camera lens, we perceiving it as glare.
Now, how to fight with it. One can add glare layer in post where those spots are. Or try to lessen this effect in render by lowering reflectivity of metal materials, increasing radius and samples of rounded corners. One can even try to increase sun size.
In your example i would even consider to turn rounded corners off on some materials.
