Not sure what I'm seeing here, but the scenario was - using maps in the reflection glossiness of a mirror material (for very delicate fingerprints/scratches etc) was causing the reflections of opaque lights in the scene to reflect as hard spheres/shape of the light itself. But a pure mirror material worked ok.
So to try and work out what was going on - in the simple scene here theres a single sphere light inside the opaque glass light. Mirror on the left is a pure simple mirror material (fresnel 999, reflection @ 1.0 & 1.0). Mirror on the right is the exact same material but with the reflection glossiness set to 0.99.
Causes the the sphere light to reflect with a hard edge and even with a faint halo around it.
Am I doing something wrong here?, Cant see that I am, but as it is I cant see a way of adding very fine maps to the reflection glossiness without causing this issue to happen.
Using Dailybuild Jan 16 (Afraid I cant test on a dif version right now - no admin rights on this PC)