I think the biggest risk is someone integrates AI with ballistic missile detection systems and the AI creates a false positive event (missile launch). And on top of that the country with the false positive has an alert ballistic missile arsenal of its own ready to launch for this contingency.

Ideally, the leader of the targeted country waits it out but what if waiting it out could mean losing it all? It's not a hypothetical scenario either. There were a lot of false positive events on both sides during the cold war. It's why countries with nuclear weapons only allow them to be launched by humans. That said what if the decision to launch is based on erroneous data?