Did you check the program preview to see if at least in the preview the program should run as expected? There could be many reasons why it stops after some unpredicted amount of time. For example, if rain sensor is enabled, it might be stopped due to rain sensor activation (could be false detection or false sensor triggering); it could be weather triggered if Use Weather flag is on for that program; it could be a solenoid problem (e.g. a shorted or near shorted solenoid); if you use an external script or service to interact with OpenSprinkler, the program run may be interrupted by the external script or service.