Smartthings Piezo Buzzer will not turn off


I have installed a piezo buzzer to the Alarm Out of the Konnected board. In the ST app, I have the buzzer device set up to beep for 200ms, pause for 600ms, repeat 30 times (total 24 secs). Once the buzzer starts, I cannot manually shut it off via the app - it just continues beeping for the full 24 second before stopping. Is this how the buzzers should work (i.e. is it not possible to turn it off before it's done with it's configured buzzer time)? I can see in the SmartThings log for the buzzer device that the OFF command is getting sent, but it doesn't stop until it's finished. 

(I'm also trying to use the SHM Delay BuzzerSwitch smartapp to control this - but it's not able to turn it off either. My goal is to sound the buzzer when a door is opened while SHM is armed, until either the SHM Delay expires and the alarm goes off, or the alarm is disarmed)