Apparently, if you put TWO fingers on the screen and swipe in opposite directions (one finger swipes up, the other down), the board will flip. You may have stumbled upon this by accident, just like I did. I don’t know of any way to turn it off, though.
Inadvertent Board Reversal While Playing

Apparently, if you put TWO fingers on the screen and swipe in opposite directions (one finger swipes up, the other down), the board will flip. You may have stumbled upon this by accident, just like I did. I don’t know of any way to turn it off, though.
What causes this “flip” and can I disable it while playing?