As the name implies, it’s screen space reflections. It reflects only the stuff that is also visible on the screen. In the second picture, mountains aren’t on the screen, so they can’t be reflected. The grass part is there, so it’s in the reflection.
If you want something that is independent from view angle, you’d need to capture the scene with capture cube:
Be careful however, it renders the scene twice with full color and is thus very expensive.