attached - nothing unusual, i am using it for months
2022-09-28 22:55:15.157 [WARN ] [t.generic.ChannelStateTransformation] - Executing the JSONPATH-transformation failed: Invalid path '/$.voltage' in '{"battery":100,"humidity":80.2,"last_seen":"2022-09-28T22:55:08+02:00","linkquality":0,"temperature":21.8,"voltage":3000}'
Thing topic Temp_1 "Temperatura 1" {
Channels:
Type number : temperature "Temperatura" [ stateTopic="zigbee2mqtt/Temp_1", transformationPattern="JSONPATH:$.temperature"]
Type number : humidity "Wilgotnosc" [ stateTopic="zigbee2mqtt/Temp_1", transformationPattern="JSONPATH:$.humidity"]
Type number : battery "Bateria" [ stateTopic="zigbee2mqtt/Temp_1", transformationPattern="JSONPATH:$.battery"]
Type number : linkquality "Link" [ stateTopic="zigbee2mqtt/Temp_1", transformationPattern="JSONPATH:$.linkquality"]
Type number : voltage "Napiecie" [ stateTopic="zigbee2mqtt/Temp_1", transformationPattern="JSONPATH:$.voltage"]
}
Show us the GUI view of your suspect channel using the code tab. Compare with a channel that works.
It is possible for unprintable characters to end up in your xxx.things file, often as a result of copy-paste editing, which will usually be invisible in your editor screen.