Blue Smart IP22 Charger 12/30

Hello Victron / Community
I have a problem with the Cerbo GX and the Blue Smart IP22 Charger 12/30. I have a test program that reads the values ​​from the charger via Modbus. In the Excel documentation, the UnitID 226 (com.victronenergy.charger) and the register 2317 (/Mode) are documented as ‘writable’. I write one of the intended values ​​into the register using a test program and get an error message on the Cerbo GX:

@40000000672cb86f0f6dd24c ERROR "Error processing function code 6, unit id 226, start address 2317, quantity 1, src 192.168.181.10: SetValue failed on /Mode"

On the Cerbo GX under /opt/victronenergy/dbus-modbustcp are the files attributes.csv and unitid2di.csv. In the file, the register mentioned is also defined as ‘writable’:
root@einstein:/opt/victronenergy/dbus-modbustcp# grep 2317 attributes.csv:

com.victronenergy.charger,/Mode,i,0=Off;1=On;2=Error;3=Unavailable-Unknown,2317,uint16,1,W**

The definition of the unit:

root@einstein:/opt/victronenergy/dbus-modbustcp# grep 226 unitid2di.csv:

226,279,Cerbo GX VE.Direct port 1 (ttyS7)

If I use the test program to switch the relay in the Cerbo GX on/off via Modbus, the communication works perfectly. If I now change the mode of the charger, I get the error message mentioned above and the corresponding response in the client:

SEND> unit=226 register=2317 value=1 Mode
qt.modbus.lowlevel: (TCP client) Sent TCP ADU: "032b00000006e206090d0001"
qt.modbus.lowlevel: (TCP client) Response buffer: "032b00000003e2860a"
MODBUS: Error: QModbusDevice::ProtocolError Protocol error
MODBUS: Reply error: QModbusDevice::ProtocolError

Is this bug known? Any solutions?

The test program is here: