Playing on the May 9th update for Xbox One, I played a service to see what performance was like on my One X, however I've noticed while playing on service *1A02 Bristol Temple Meads to London Paddington* the in-game sun is missing it's texture/shader (you can see the sphere object), however entering free-camera the sun is clearly visible. Shadows are still in the correct positions however. I found this under the following weather conditions: Summer Clear (with all other effects set to default) I tried a different service in Spring Clear however all seems fine there, tried another service in the summer setting and can replicate the issue. (included two screenshots to show cab-view and external. Not a major/game-breaking bug but thought it was worth a mention. Edit: Build #178 - The cab-view screenshot you can see the sphere in the sky in top left corner.
Erm.. Did you check behind the blind? Update - I can confirm the sun is hiding behind the blind in the cockpit view as the grey sphere is also visible in the free camera mode on your screenshots.