Shelly Binding and Google Home - Brightness control


I have some trouble with the Shelly Binding in combination with the Google Assistant integration.

Short Overview:
Shelly RGBW2
Firmware 20201124-092159/v1.9.0@57ac4ad8
RGB Mode

OpenHAB 3.0.1
Channel color#hsb linked to Item Test (Color)

I can control Color and Brightness over the openHAB Web interface, for example Color Red 71% Brightness:

2021-02-02 19:54:18.847 [INFO ] [openhab.event.ItemCommandEvent      ] - Item 'Test' received command 0,100,71
2021-02-02 19:54:18.847 [INFO ] [penhab.event.ItemStatePredictedEvent] - Item 'Test' predicted to become 0,100,71
2021-02-02 19:54:18.847 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'Test' changed from 0,100,21 to 0,100,71

Now I change the Brightness to a lower value to see the difference e.g. 10%, after that I open the Google Home App (Brightness 10% is shown correct) and set the Brightness again to 71%

2021-02-02 19:57:23.238 [INFO ] [openhab.event.ItemCommandEvent      ] - Item 'Test' received command 71
2021-02-02 19:57:23.254 [INFO ] [penhab.event.ItemStatePredictedEvent] - Item 'Test' predicted to become 71
2021-02-02 19:57:23.254 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'Test' changed from 0,100,10 to 0,100,71

The Slider in the Webinterface changes also to 71% but the Shelly controller remains on 10% Brightness.

The only difference I could find, that the command coming from Google Home is not the same as if I set it from the Webinterface.

But in the end i would compare the change event which is the same… or do I miss something?