Ah, yes... I can indeed see the difference now.
In fact, there always has been a difference with how gamma is dealt with between the WL and the EE renderer (the latter rendering shiny prims slightly brighter, materials a bit darker, etc), but there is indeed a worsening of this effect with a bug introduced in v1.28.2.46 (I did not notice it so far because the existing difference only got a bit worse)...
To fix that render glitch, simply change line 422 of linden/indra/llinventory/llsettingssky.h to read:
(i.e. the smear() was missing and the '+' became a '*'... My old eyes were probably very tired when I wrote that !).
Fixed for next release.