When I enable debug logging in the MySensors Home Assistant integration I notice I get a fair amount of entries that seem to have nothing to do with MySensors. This includes notification updates, WiFi connection failures, etc.. Is this normal?
You write "...clicking is heard..." Is that a single click or a click click click ...?
After getting the LOW signal, wait a period of time and if it's still low, send the message that there is a flame. Likewise for a HIGH signal.
Perhaps instead of a relay, an opto-isolator?