For context: In my workflow, all essential managers are saved as prefabs that get instantiated when the game initializes and dont destroy til the game stops:

The issue occurs in play mode.
If you either open or just click on the audio manager prefab in the project window, OnValidate() gets triggered but it doesn't detect that this is a prefab asset and will run EstablishSingletonDominance () anyway.
Thus the AudioManager Component gets disabled on the original prefab.
This is annoying and generates errors because the next time the game runs it instantiates the prefab with the disabled component.
For my specific situation i can do a dirty fix and just ignore the re establishment of the instance because i know there's never more than one of them but it'd be good to find a clean solution to this.
Does "EstablishSingletonDominance" really have to run when OnValidate? Couldn't it be run on awake?
Unity 6.0.38, using the latest version on the dev branch
Cheers