If you have all your zones on the same flex schedule, and are using the ‘before sunrise’ scheduling option, the start time is calculated assuming all zones will water. You may have missed the start time for the overnight cycle, if the total run times are long.
If you click on the raindrops under each day on the scheduling page (e.g. under the 17), you can see what watering is planned for each day. If you go the zones page, it should tell you the next planned watering for each zone.
If Rachio thinks your zone is dry, it will schedule a watering the next time the flex schedule for the zone runs.