Hello,
the viewfinder of all M-cameras from the M 2 to the M 6 have more or less flare when a very intensive light source is a little bit outside of the frame. The only exception is the M 3 which has a tolly different viewfinder. My M 6 had to be sent in for repair and by this opportunity I let exchange the front glass against the multi coated one from the MP 0.72. The result was that now the red LED's are so extremely bright, that it is sometimes difficult to balance them for equal brigthness. I contacted Mr. Erwin Puts and he confirmed my observation.