Its most likely due to the fact that the timeline in Scene2 has no where to go at the end of it.

What I mean is that at the end of a timeline, if there is no where to go or you dont tell it to do anything it will go back to the start of the timeline. If there is any other scenes, then the timeline will go to the next available scene.

You most likely have to put a stop(); action on the last frame of scene 2 or have it go somewhere.