Like a phoenix from the ash(cloud)es…

You are the Head and only judge of a Standard Grand Prix Trial. You are called to a table where the players are finishing Game 3. Nathan tells you that Ashley just won the game by attacking for lethal and didn’t reveal her morphed Ashcloud Phoenix after the game ended. Both players agree that the Ashcloud Phoenix was killed two turns earlier by Nathan’s Lightning Strike while it was face up and returned face down by its own triggered ability. It has remained face down since then. What do you do?

Judges, feel free to discuss this scenario on Judge Apps!

[expand title=Answer]As many of you noticed this has not been a game loss neither before nor after the recently published change in the IPG. Before the situation was as follows:Ashley forgot to reveal her morphed Ashcloud Phoenix which is a Game-Rule Violation since c.R. 707.9 was broken. The IPG tells us that “An error that an opponent can’t verify the legality of should have its penalty upgraded. These errors involve misplaying hidden information, such as the morph ability or failing to reveal a card to prove that a choice made was a legal one.”. In this case none of the two examples applies since both players know what the face-down creature actually was when it was returned from the graveyard face-down so there is no point at which the legality of that creature being on the battlefield face-down was questionable and thus the infraction should not be upgraded.
The new language can apply when an unknown Morph isn’t revealed.[/expand]