Maybe some pages are 24 hours. Could you let us know the pages which is 24 hours? Our default watering is morning unless there's not enough time for watering in the morning. Watering changed to PM watering is not caused by weather provider. It does not matter which weather to choose.
It is possible that it is in the afternoon when you change the watering, so the watering activities can only be scheduled in the afternoon. Watering should be in the morning in your following watering schedules.