Heavens Above doesn’t track every piece of space junk, of which there is a lot. A tumbling booster state is possible, but they’re typically dropped before reaching orbit. There are also things like discarded panels, interstages, etc. One astronaut was working outside the ISS and lost a whole tool kit.
Yeah, it looked like a largr cylinder going end over end, causing the light fluctuation. But it was with some cheesy high power binocs so I had to guess it was not very high if I could see the shape. Might have fallen sometime after, from someone’s launch.