MSMessage summaryText not consistently displaying participantIdentifier string

Question

I'm having trouble getting the summaryText on a message to consistently display the name associated with the UUID that is passed forward. When it fails to work only an empty string is displayed in its place.

        let local = activeConversation!.localParticipantIdentifier
        let remote = activeConversation!.selectedMessage!.senderParticipantIdentifier

                if winningPlayer.id == localPlayer!.id {
                    layout.subcaption = "$\(local) wins!"
                    message.summaryText = "$\(local) won \(scoreForLocalPlayer()) - \(scoreForRemotePlayer())"
                }
                else {
                    layout.subcaption = "$\(remote) wins!"
                    message.summaryText = "$\(remote) won \(scoreForRemotePlayer()) - \(scoreForLocalPlayer())"
                }

What's especially strange here is that the layout.subcaption always shows the correct name, but the message.summaryText usually only displays " won 1 - 0" rather than the expected "(Winning Player's Name) won 1 - 0"