It was hardly a secret since Trump is on video gesturing to get Putin's attention and it was obvious from the hand signals that he wanted to chat. What they talked about is anyone's guess but they did have a nice long chat.
If the media is touting this as a "secret meeting" obviously anyone who takes a passing interest in getting their own news would know that headline was nonsense.
I thought it was a bit rude to abandon his dinner partner, Japan's First Lady but maybe she was relieved.