Please make sure that the device’s firmware is up-to-date. Use the eWeLink app to check and update via Bluetooth.
Re-install the driver: delete the device in ST, delete the driver, install the driver, re-add the device. This procedure makes sure that everything is initialized correctly. The driver itself supports driver switching, but who knows if the device accepts certain settings only after pairing - it’s a sleepy (and buggy) device after all.
Very important: go through the settings and change the Device-side watering limit. The default is still 10 minutes, because that’s the factory preset default on the hardware itself (at least in some firmware versions).
I also need to know your model and the current firmware version.