Balloon or UAP (Able test 1946)

I have an old recording of the Trinity and Beyond the atomic bomb film from 1995. I watched it again a few days ago, and I saw something that at first looked like an error or flaw in the film. I repeated it again in VLC-player, and clearly it’s not an error. The scene is from fourth nuclear detonation, the Able test in Bikini atoll from 1st of July 1946. Maybe they launched some balloons for scientific purposes, or it’s something else. There is also a newer version of Trinity and Beyond film, the 70th Anniversary tribute. It looks like that version doesn’t include this 2-3 seconds clip with the metallic looking sphere or a balloon. I’m not sure, is it legal to post a link to a whole video of the film, which someone else has uploaded to Youtube. You can find it yourself by using keywords: Trinity and Beyond – the Atomic Bomb movie (point where the clip can be found 19:41-19:43).