Yeah, skip the behaviour and control your camera with events. Use every tick as the condition, then "System -> Scroll To position" actions allows you to set the exact point for the scrolling, and if you use the lerp expression for this as well, you'll get smooth scrolling. (if needed of course)
Then you just set it to scroll to Player.Y - Offsetamount.
Or for smooth:
lerp(ScrollX, Player.X, dt*scrollSpeed)
lerp(ScrollY, Player.Y - offset, dt*scrollSpeed)