The Leica 50mm f/2 APO-Summicron-M ASPH is a $7200 lens that is a superlative performer in nearly every way. See the extensive review coverage in Guide to Leica as well as the extensive review coverage of all Leica M 50mm lenses.
I have added another retina-grade example of veiling flare performance both shaded and unshaded to the Leica 50/2 APO ASPH veiling flare under field conditions page.
Will Leica do anything about the veiling flare behavior? This in my mind is the antithesis of what I expect from Leica, certainly for an f/2 lens, and at this price it is more than a bit unwelcome as a constant hassle in the field (having to shade the lens under so many interesting lighting conditions). At the least I would like to see Leica provide a more effective clip-on or screw-in lens hood, because the elegant built-in lens hood is ineffective.
See also my other evaluations of flare with Leica M and Zeiss ZM lenses.