Strange issue when trying to set Tado X Thread network as preferred network

I’m trying to set my Thread network (Tado X devices) as the preferred network so that I can add new devices to it. I followed the usual steps:

  • Open the Thread integration in the Companion app, select the Tado network (named tado-55de, the only one on the list)
  • Click “Send credentials to Home Assistant”
  • Open HA in the browser and open the Thread integration
  • The “Make preferred network” option is now available

However after clicking the button to make it the preferred network, I now see two networks: a preferred network named tado-ba36, and the old network, still listed under “other networks”, and without an option to make it the preferred network.

Any ideas how to fix? I tried adding the new device to the Thread network using the Tado app, but it does not recognize the device.