Yes, there should be an audible pre-closing warning the plays at the same time as the blinking LED. Please try changing the sound in the firmware settings to the default sound (make sure you build & update the firmware after doing so). If that still doesn’t work, then there may be a hardware issue with the device. Reach out to us at help@konnected.io to further troubleshoot.
It is a known issue that the partial opening/closing only works (on most openers) in the opening direction. This is something we’re still investigating and may be fixed in a future firmware update.