Setpoint on Vitodens 200W jump from 20°C to 10°C setting setpoint on Tado from 20°C to 19°C


I just have installed my new Tado Smart thermostat following the different steps. My Tado is connected to a Viesmann boiler VITODENS 200W B2HA - 26KW with Lamba Pro control sonde VITOTRONIC 200 HO1B. I have restarted my installation, made the changes in the boiler settings. The set point on the boiler stay at 10°C even if I change the set point on the Tado. Additional information it looks setting the setpoint above 20°C is accepted as setpoint for the boiler, everything below 20°C set the boiler setpoint at 10°C ??? Please advise. Thank you