Alti-2 Digital altimeter

I just bought the Altimaster Alti-2 Neptune digital altimeter. Whenever I was around 1000 ft, the screen went from the screen that displays the altitude to the main screen. Any ideas? 

I've hundreds of jumps with the thing, but for the life of me I can't remember if it switches automatically between screens at 1000ft or not. 

Mine is usually on the main screen on the ride up, changing betweens screens can be done manually by pushing the button bottom right.

After detecting exit the Neptune will go to altitude display automatically.