Hello , Sometime ago i read that if you have 3 copys of a unique card and a bad greyjoy cancel the salvation of discard a copy, you can´t trigger the second copy to save that card,

Where can i find that?

Thanks.

I'm not entirely sure what you mean by "bad greyjoy cancel the salvation of discard a copy."

BUT I think the answer you're looking for is this: If you have two duplicates on the same unique card and the first is canceled, you CAN use the second. Since the two duplicates are considered to be separate and individual cards/effects, using the second after the first one is canceled does not violate the "one response per trigger" rule.

The "one response per trigger" rule stops you from using one response card two times. It does not stop you from using two different separate and individual cards one time each - even though they do the same thing.

Then you cant use the location grey that have 2 gold to save the same character 2 times?

Then you cant use the location grey that have 2 gold to save the same character 2 times?

Correct.