First run of zone doesn’t work

I have 4 zones configured on an 8 zone unit that’s running the current firmware. It’s configured with Flex Monthly, and this results in a run about every 7 days.

The first run of the first zone seems to not activate the water in that zone. Subsequently the next zone works fine, and when it gets around to the first zone again in the schedule, it too works fine. All zones work when selected via the manual button, or the app, for a quick run,

Any ideas what the problem might be?