That’s not quite true. It’s clearly to do with an MQTT binding channel, and clearly one that involves on/off.
I agree it is a shame it doesn’t say which channel, and leaves you to work it out.
How did you work it out? Meaning are you confident you are looking at the correct channel.
Okay, you have both a MAP transform and the Custom On/Off values set here.
From many other posts these do not play nice together - I think the MAP happens first, not sure, but then it will will fail the custom on/off lookup.
An important point is the Custom values affect both outgoing and incoming, and you do have a commandTopic set, so you are using outgoing.
Presumably you are happy that openHAB commands ON/OFF are published as “on”/“off” payloads?
If so, and if the incoming status payloads are also “on”/“off”, just do away with your MAP altogether and leave the Custom values.
Else, if you need different incoming and outgoing payloads, you will have to do separate transforms and remove the Custom on/off values.
When people have got in a mess with their logging before, the easiest escape has been to restore the whole default cfg file