I'm Gonna Wreck It!
Tonight we included these cards for the first time.
We noticed that the cards all have an "immediate effect", while some have an "ongoing effect" also. Clearly the ongoing event stays in the game, however the immediate effect usually makes absolutely no sense unless they remain in the game for some amount of time.
We had to pick a scope for them, and so we agreed to play that the "immediate effect" cards were good for the next player's turn and were discarded once the next Darkness Spreads cards were drawn.
What's the actually intended scope of an "immediate effect"?
I'm sorry you haven't had this question sooner. I just noticed it myself.
But your question is actually answered here
Global Event Cards clarification