This issue only occurs on iOS and does not reproduce on Windows or Android. I have seen that the SceneDepth value of the DepthFade node may not be compared correctly.
1. Open the attached project
2. Launch on iOS.
3. Material using DepthFade will give an error like Depth banding
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-79979 in the post.