Game: Halo 3
Issue: Broken model lighting
Info: The first mission I played was Arrival. Everything looked normal until I got about halfway into the next mission, Sierra 117. I noticed that when I switched to the magnum in broad sunlight, Chief's arms and the magnum itself were way darker than they should have been, almost completely black. As I went on in the mission, more and more models shared these problems. The marines that fight alongside the player are completely black except for a few pieces of their armor and their faces. When I died I noticed that Chief's body was completely black except for two pieces of his armor. It is also worth noting that only weapons (both factions) and allies were affected by this glitch. I did not notice any Covenant that were affected. Once I finished the mission everything looked normal again and unfortunately I was not able to reproduce the issue again.
The campaign settings I had used were mostly default, except I was playing on normal difficulty and I had the IWHBYD and Grunt Birthday Party skulls enabled. At the start of Sierra 117, I had paused multiple times at the beginning of the mission to adjust the look sensitivity.
The link to the screenshots is at the top of this reply. The source files uploaded from the console are there but unfortunately HDR was enabled while I was playing so the images appear darker than they would on my TV. I have also included the screenshots that display on Xbox.com because they are much brighter and easier to see compared to the source files. The names of each image in the Xbox.com folder indicate the points of interest in the image.