This started happening recently in 4.13 integrations.
StartCameraFade node no longer has any effect.
Fading no longer works in new VR Template.
Either Add new StartCameraFade (or test in new VR Template which includes the mechanic)
For fresh project:
Add StartCameraFade to beginplay of a basic pawn. Fade it to any color eg. Black.
Result: nothing happens anymore.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-34143 in the post.