I do not have a restriction on days and have my schedule set to Any day for Flex Daily. I’m having the same issue. Each day predicted rain and it didn’t rain.
I did a quick run on the schedule yesterday to try to prevent the grass from dying further. The run started immediately which was around lunch time. Sure would be nice to be able to tell it either now or tomorrow where it would override any predictions/rainfall and start to function like the schedule was created. In my case that would have end before sunrise. Then my watering would have been better as opposed to during the heat of the day.