I just activated Sprinkler Plus yesterday, it created a schedule for my 5 zones and ran it early this morning. It is now 12:30 PM and we just had a storm roll thru that dumped .86 of an inch of rain! So much for Sprinkler Plus reading the forecasted weather and adjusting.
That is weird.
Is your soil saturation showing at 100%? I am just wondering if maybe it saw there was rain coming, but determined your saturation level was really low or something. Or maybe it’s because you just barely activated it so it also thinks it was at 0% saturation? Just guessing. I still would’ve expected it to skip watering today though. 
So far today we have had 1.36 inches. After the initial schedule ran it was not scheduled to run again until 6/29 and its still that way.