Probably more info than you want, but there is a nice table that shows the different max runtimes for soak cycle. It’s a little buried in this support article: https://support.rachio.com/hc/en-us/articles/115010379767-Smart-Cycle-and-manual-cycle-and-soak-features
Go to FAQ and then "How long can a zone’s watering duration continue before it needs to get cycle soaked? "