Western Star Condens communication error

Hi everyone. I also have a Tado V3+, which I’ve connected to a Westen Star Condens 24 boiler. The issue is that when the temperature is set to 22°C, the system kicks in at 21.9°C—but it only fires up for about 30 seconds. Even though there is still a demand for heating, it fires up again 3 minutes later, runs for another 30 seconds, and then stops again. However, if I increase the target temperature to 23°C, it modulates the flame perfectly. What could be causing this?