Satch:
If your home completely loses power, there’s no way your internet wouldn’t drop unless you have an UPS or other battery backup device. You could try an experiment by opening your main breaker and timing how quickly your generator starts and stabilizes from a “black start” and how long it takes for your load to transfer. At best, the whole process would take between 15-20 seconds or longer.
Edit: It might be possible that the duration of power hit was brief enough to start the generator without actually transferring the load.