GKTurnBasedMatch doesn't consistently advance to the next player (Xamarin, Apple GameKit)

Question

I'm using a turn-based match for a board game, and when a turn is complete I call GKTurnBasedMatch.EndTurn and pass the match participants and the new match data as the arguments. I need the game to advance to the unmatched players, but it only does so after some indeterminate time related to the timeout value. Setting the timeout value 0 only prevents the game from ever progressing past player 1. The match data is being updated, so the app is definitely communicating with Game Center servers. What am I missing here?

private void endTurn(double timeout)
    {
        // Copies list of participants to a mutable array
        GKTurnBasedParticipant[] Participants = new GKTurnBasedParticipant[match.Participants.Length];
        match.Participants.CopyTo(Participants, 0);

        // Advances to the next player
        match.EndTurn(Participants, timeout, matchData, (e) =>
        {
            // If there is an error message, print it to the console
            if (e != null)
            {
                Console.WriteLine(e.LocalizedDescription);
                Console.WriteLine(e.LocalizedFailureReason);
            }
            // Otherwise proceed normally
            else
                turnOverUpdate();
        });
    }

Answer 1

Apple's documentation is quite poor for the EndTurn method, but I figured it out. The NextParticipants field should be treated like EndTurnWithNextParticipant, so you have to copy GKTurnBasedMatch.Participants and reorder it so the next player is first and so fourth. The match only gives you the participants in order of joining, not relative to the local player, so you have to sort it. Below is the code I used to accomplish this.

        List<GKTurnBasedParticipant> participants = new List<GKTurnBasedParticipant>();

        // Gets the index of the local player
        int index = 0;
        for (int i = 0; i < match.Participants.Length; i++)
        {
            if (match.Participants[i].Player != null)
            {
                if (match.Participants[i].Player.PlayerID == GKLocalPlayer.LocalPlayer.PlayerID)
                {
                    index = i;
                    break;
                }
            }
        }

        int offset = match.Participants.Length - index;

        for (int i = 1; i < offset; i++)
            participants.Add(match.Participants[i + index]);

        for (int i = 0; i <= index; i++)
            participants.Add(match.Participants[i]);

        GKTurnBasedParticipant[] nextParticipants = participants.ToArray();