Well, I think they were talking about the absolute difference between gravity or not of an object. It’s not really subject, we just don’t know at what point that happens because we’ve largely only been working with orbit made.
We lose thousands of tons of mass every year in the form of gases and gain a lesser amount in material from asteroids over the same period. The mass gain appears to have been quite dramatic, back when the earth was formed. Chaos would have reigned for a significant period after that, then we would likely have had a constantly diminishing amount of asteroid impacts. When exactly the earth went from a net annual gain of mass to a net loss is hard to say, but if you were to ask if the mass of the earth-moon system maintained an annual net zero mass change at any point, the answer would probably be “We don’t know for sure.”
