The JSONPATH tranformation you are trying to apply is not a valid path for whatever message is being published to the topic.
What you need to realize here is that because your device is publishing different JSON messages to the same topic for each device, two of the three Items will generate an error for each message. For example, if {“temp”:“20.1”} is published to home/BLEGateway/BTtoMQTT/C47C8D6A3826, whz_blume1_fer, whz_blume1_lux, and whz_blume1_moi will generate errors because the message doesn’t match the JSONPATH for those Items.
If you are using the 2.5 M1 version of the binding, you can chain transformations and put a REGEX transformation first to match only those messages that you care about. See MQTT 2.5 M1+ How to implement the equivalent to MQTT1 REGEX filters for details.
If you have control over how the device publishes it’s readings, it would be even better and more appropriate to have it publish the sensor readings to separate topics in the first place.