Meadowlark

Challenges: Kneel Meadowlark to choose a challenge icon. each character in play loses all enhancements on that icon.

no "until the end of phase/turn"?until the end of the game?

I believe since this has a point of initiation it will last until the end of the phase. I'm no rules expert so if someone else says something else listen to them.

Shadowcatx said:

So yes, as written, this effect would last for the entire game. It will need errata at some point to include a duration. However, in similar situations from the past, where a duration was pretty clearly missed (think CS-Illyrio), the practice has been to pretend there is an "until the end of the phase" duration until that official errata is released. (So the original answer has the right idea, just over-states it as a general default applicable to all effects.)