Run routines through Alexa

I have a virtual switch DTH with a variable (configurable) off if you would like to try it?

You can configure it for a 5 second off and that would sort your issue out.

https://github.com/CobraVmax/SmartThings/tree/master/devicetypes/cobra/custom-variable-switch-seconds.src

Seems to work reliably for me (used for the same thing)

And here is info on installing if you are not familiar with it: