Using Unity 5.0 Alpha 2 when I click the Play button the viewpoint in Scene view zooms. For example, if Scene view was zoomed in on some small portion of the level, Playing the level in Game view would cause the Scene view to zoom out. I do not remember this happening with earlier versions of Unity, and I explicitly verified that this bug does not occur using Unity 4.5 beta 4.

Since the viewpoint is automatically zoomed but not panned or dollied, the workaround is to simply zoom in (or out if applicable) after clicking the Play button.