Nah, it builds hype for the next season. Jon Snow has to be the most popular character behind Tyrion now. And he might be more popular than Tyrion. Should be, since tyrion was pretty lame this season and Jon was pretty kickass.
Plus the season just ended. So it's not like anyone gives a shit. Jon getting ressed is an extremely popular fan theory.
And she really isn't spoilering anything. She's making references to what actually happened in her scenes in the show.
She's doing PR. Someone at HBO probably even told her to do it.
This season had 4 or 5 good episodes, and really only 2 of those were REALLY good. It wasn't a great season compared to the others. And worse, if you look at it in a vaccum. Which would be sort of dumb to do, but the point is... honestly not their best work. So they're gonna need to rely on the actor driven hype train more than they have been. The materiel is starting to get weak.