Honestly the whole thing that she "eviscerated" her in the debate (as the New York Times put it) is a bunch of horseshit.
Here's the exchange. I think Harris was a little taken aback because it was at least 50% complete fabrications, and that's harder to deal with in a debate setting than in a prosecutorial setting. It's fair to say she handled it a little poorly and Gabbard did a good job at landing the dishonest attacks. But most of what it accomplished, at the end of the day, was to accelerate the putting of those lies into the public discourse in a big way as talking points, alongside the idea that if anyone in Harris's office was prosecuting people who broke the law at the time, that represents a fair reason to attack Harris today because obviously what she should have been doing was letting them go and instructing every prosecutor in California to do the same, and that wouldn't have caused any problems.