Unity crazy null reference exceptions for no reason

Hi, i'm having a very strange problem in my project, It happens randomly when I open the project and start the scene, the console give me a lot of random null reference exceptions of a lot of prefabs that I know they have the reference because I dragged them In the inspector so It can't be possible. The strangest thing is that when I open some random script and save it, Unity recompile the scripts, the null references disappear and i don't have these errors anymore, but when I re-open the project It happens again the same thing. Do you have any idea of what's happening?