We’d need to see your actual trigger. I don’t think that sending “on” repeatedly should result in a state_changed event that would cause problems, but I supposed it could.
Edit: And yes, what finity suggests will provide a clue as to whether the entity has actually changed. But if only an attribute changed, I would expect last_updated to change, but I wouldn’t necessarily expect that trigger to reset.
Thanks, that Dev Tool monitoring helped me. It actually does change it’s state, but not on “on” → “on” transitions, it actually changes from “on” to “unavailable(1sec)” to “on”.
This is because the device loses MQTT connection every couple of minutes (Wifi is 88% though). Now I have to figure out why this is the case. At least the automation behavior is explained.