How does the second atomic bomb projection prevent the plane taking pictures from arriving at the scene ahead of time?

In order to avoid the plane arriving at the scene in advance, they are required to check with Iwo Jima and Tianning Island before flying over Iwo Jima. If you have doubts because of insufficient information, the camera plane must shoot two targets. But for some reason, the B-29 bomber in charge of photography failed to reach the assembly point of Yakushima on time. The pilots of the first two planes circled anxiously in the air for 45 minutes, but they still couldn't see their partners. Finally, with the consent of the commander, they flew to their 1 target-Kokura in Kyushu (where there is an important Japanese arsenal).