How's the rest of the light? Any response to what firemedic is experiencing?
The rest of the light seems perfectly fine. Firemedic's main complaint appears to be brightness vs his other H502; I don't have any other H502 model, so I can't comment. I do have a late model SC31 running on lithium-ion that seems comparable, but the large difference in beam shape makes it decidedly unscientific.
I have noticed that bare LED's seem to have a bit of corona to them. I wonder if there's something in that? The cool white XM-L in my malkoff mag dropin has a greenish corona. I didn't really notice it before but I usually have the reflector on. There were people complaining about the corona in the cool white H502 too, with much blame on the GITD reflector.
I'm fairly certain the majority of the effect is not due to the GITD reflector. I can stare directly at the LED and watch the surface of the LED change color as I approach the edge of the beam. The brightness of the LED vs the GTID material leads me to believe that the GTID material has little to no effect on the color of the beam (unless the GITD light is being reflected back onto the surface of the LED).