I think it is a Tony time travel, but I'm not sure. Gen or possibly background Tony/Pepper.
Tony is not part of SHIELD, and he has done a lot to create a good reputation for himself and his company.
Steve only has info given to him by SHIELD, and he thinks very poorly of Tony. He volunteers to assist with cleanup of NY (just after original Avengers movie?), and unwittingly talks to an undercover reporter. He says several disparaging things about Tony/Iron Man.
When the article comes out, it's critical of Captain America, and SHIELD has to do damage control. One of the points is Steve had no idea what a nuclear bomb was and why it was such a big deal for Tony to fly it into space.