> Do we understand the mechanisms of this "genetic memory" (my words, no idea if its accurate or if there is a better word for it)?

It’s not actually a memory that gets encoded in genes.

It’s a tendency to behave in certain ways as influenced by combinations of genes

Ancestors who had the same tendencies, drives, and preferences would have some similar behaviors, resulting in some of them going toward the same places.

So not an actual memory that gets inherited, more like personality traits (but in a more general sense) that lead to similar outcomes.

There is a field of epigenetics which studies heritable changes in cells that occur without DNA alteration, but these signals are much simpler than memories and not a mechanism for carrying memories across generations. A lot of pseudoscience has been written around epigenetics right now so you have to be careful about where you source info on this.