I saw that too. And it must be; it strains reason to think there was some other piece of space junk at exactly the same place and speed.

Of course. I just expected them to fall at the same rate.

They did fall at the same rate, to very high precision. That booster was going like 2000 km/h! The delta is tiny, and likely down to the very low but non-zero aerodynamic accelerations that will differ between objects of different shapes and densities.