As far as I understand it the B-Hyve unit queries the weather for the nominated weather station just once, just prior to running a program. It’s only as accurate as that weather station. I have quite a few clients for whom I installed B-Hyve timers and run my own weather station feeding pwsweather.com which is where B-Hyve pulls it’s weather from.
Check the two zones with a voltmeter at the B-Hyve controller. You should 24 to 26v AC between com and the zone contact. I would guess it’s the valve sticking. Once zone 2 closes there will be more pressure to shut zone 1. If so, unscrew the solenoid, clean it, oil it, replace if necessary.