Workaround: The problem shows up when import settings format for the image is overridden with 16-bit format. This can be fixed in import format settings override pane: click on the icon -> Inspector -> Phone icon right of "default" -> Format. Either deselect the "Override for iPhone" checkbox or select "Truecolor" for the format.

To reproduce:
1. Open the attached project or create a new iOS project with a white app icon.
2. Build the Xcode project
3. Go to the Xcode project files and with an eye dropper app check the color of the icon. Notice it's not truly white.