Collectible Card Game Headquarters

Elesh Norn, Grand Cenobite's ability is incomplete by the looks of it.
When it enters the battlefield, it gives -2/-2 to opponent's creatures permanently.
However, any opponent's creature that appears after it is unaffected, and the 2/2 can survive.

I attached a save file.

The opponent has Boartusk Liege also modifying P/T