Device.present causing unexplainable slowdown

Hello. I've been working on an Android game for some weeks now and i am facing the following problem. Right now the game consists of 3 scenes: Splash, Story and Game. Sometimes the game will launch just fine, achieving a smooth 60fps from the Story to the Game Scene. Other times the game will launch with a terrible 15fps, which the profiler shows is mostly due to device.present taking up to 80%. That can happen if i terminate the app completely and i also recall it happening even when the phone screen dims while on Story and i press to wake it up. The slow fps will continue through to the Game scene. I know similar questions have been asked before, but i haven't find someone else reporting such inconsistent behavior.

Unity version is 5.4.0f3 and the testing device is a Galaxy Note 5. I am using Application.targetFrameRate= 60fps. Below are 2 screenshots of the Profiler window, taken at roughly the same time into the game, showing the difference i'm talking about.

Thank you in advance