Lost all electrical, then it came back. What's going on here?

Something got hot quickly, expanded, and broke connection. It re-established connection after it had some time to cool. Along with all the bulkhead connectors, I would make sure that fusible link connection is solid. What you experienced is exactly what happens when the fusible link goes open-circuit, except the fusible link doesn't come back. It's great fun losing it at nearly triple-digit speeds northbound on I-43 at 2:30AM, trust me. You lose everything but your ability to pray.