formatBeforePublish will not work

I will post the Power data from my shelly in openHab 3.4
The values are shown right but I need a suffix like Watts after the numbers.
I use formatBeforePublish with %s,Watt but it is not shown on the page.
This is the code of the thing:

  - id: solarpower_total
    channelTypeUID: mqtt:string
    label: Solar Power Total
    description: ""
      formatBeforePublish: "%s,Watt"
      stateTopic: tele/tasmotasolar/SENSOR
      transformationPattern: JSONPATH:$..ENERGY.Total

See in the german forum:
Maybe consider not to ask in multiple communities at once but wait at least some hours, especially when it’s night in Germany :wink: