froma cnbc article July 18, 2019, cites a Kuwaiti paper of the July 2018 flight
https://www.cnbc.com/2019/07/18/f-35-has-freaked-out-iran-and-changed-everything-in-the-middle-east.html
"Yet the most direct effects of the F-35 were still to come. In July 2018, a Kuwaiti newspaper reported that Israel had flown a test mission of at least three F-35 jets to Tehran and back from an airbase near Tel Aviv. While never confirmed publicly, a good number of military and political leaders in the region believed and still believe the story. The long-rumored threat the F-35 posed to Iran now seemed like a reality."