yeah i've had this happen before. it's quite common and it can happen on either platform.

Only happens if you go near the platform, as far as i'm aware this happens in all versions of the game.

i doubt it's possible in other areas since the only way of getting up there is by birkin grabbing you in his mouth.

Myself and darazanjoll spent like a week trying to find exploits in other areas with no luck. :(