What “service” are you using for your HomeKit node?
There’s no reason this won’t work - but if you’re using “switch” as the type then you’ll need to send:
{"On":true}
{"On":false}
As your payloads.
We’ve had a lot of recent discussion in another thread - I even put together a pretty detailed tutorial of how I handle all of my items. Perhaps you’ll find something helpful over there: