It may be helpful to recognize that gravity doesn't exist, it is a second-order effect of the shielding of electromagnetism by standing wave matter. The force is not gravity but equilibrium-seeking in Coulomb's law.
If you imagine a completely empty space with the base constant values for electric permittivity and magnetic permeability, this homogeneous space has no real "gravity" to speak of (ignoring transient particles emerging from the aether). Now add some matter to this uniform space, let's say two spheres are added. Now there is an uneven mass distribution in this space, and the base values for permittivity and permeability are altered. We find that the values are higher or lower depending on the location we sample in the space, and as a result, electric and magnetic forces result in motion. We also find that there is a shielding of the constants by the matter as it is occupying space and changing the parameters there, as well as behind it which depends on the vector between the observer and the object, or the space behind it.
The memory effect is the consequence of this disequilibrium resulting in motion and chemistry that would not have otherwise occurred without the imbalance and that is a function of the mass-distribution of the space. The inferred gravitational force (really coulomb's law) and motion occurs to minimize this imbalance. That the imbalance no longer exists, maybe your black hole evaporated, doesn't matter, there is evidence that there was a disequilibrium at once point based on the way in which is was resolved, which is encoded in the new distribution of matter and energy. One can then infer previous mass-distribution states by analyzing the current state.
Gravity is imaginary, a useful but sometimes limiting simplification of the complex matrix of space constant deviations.