When using the Play camera shake on the player controller, it stopped automatically after one frame.
HOWEVER the duration of the oscillation was set to -1, which means indefinite. So one would expect it to keep looping, which it is not. So when i tried it with a duration of 10 seconds, the shake played fine. I suppose this means it could be a bug?
EDIT: Found in the 4.8 release notes:
Camera shakes now ignore calls to Play Camera Shake with zero or negative scales, and will allow shakes that reach zero scale to still update their oscillator so they will eventually be removed
Maybe they also ignore negative values for oscilation durations?