The Oribos skybox remains dark and gloomy in the Dragonflight pre-patch even after the Jailer has been defeated.
What’s more, the consumable which brought back the good old bright skybox (Memories of Brighter Times) doesn’t work in Patch 10.0.0 either. This is most likely a bug that needs fixing.
Oribos skybox after players complete the campaign and defeat the Jailer.
Source: Reddit