What worries me about this is two things.
First, Jeffery Goldberg was responsible and honest enough to 1) not reveal all the leaked plans (since that would be a national security problem) and 2) inform both the government and the public that it happened. How many times have top secret plans been leaked in this manner to someone who either forwards them to friends ("hey, look what I got!") or worse yet, sells them to China/Russia/Saudi Arabia? Because you know this isn't the first time it's happened.
Second, adding journalists to a chat was done without a second thought, almost as if they had done this before. How much top secret government information has been going out to FOX News, Breitbart, OAN etc?