I built a exodia incarnate deck, and tested it against the Kaiba AI because that AI is easy to beat. I tried multiple times, and each time I summon Exodia Incarnate, during the End Phase of that turn, thegame will not let the turn pass until I activate his effect, no matter what I do. I know that, at least in the English physical card version, the effect is not mandatory. How do I pass the turn without activating his end phase effect? I tried tapping the End Phase button again, and I looked around on the screen for a button that might help. Is it because I haven't updated the card database since I downloaded the app sometime in November?

The Trigger Effect of The Legendary Exodia Incarnate is Mandatory, because it does not state "You can add...".

As long as there is a "Forbidden One" monster in your Graveyard, this effect must be activated.