I had an issue with the bug, when you aiming at the sky, the sight suddenly become completely blanked out, if there an obstacle for example a building, the sight went back to normal, and if i move my sight again to the sky it went blank again.
i also realize the reticle in third person mode also disappears if you aimed at the sky, but it came back if you aiming at obstacles
here the link of the video related to the bug issue