Remove Smart Radiator Valve from my Home?

Dear All,

How do I correctly remove a Smart Radiator Valve from my Home?

I have one room with two Smart Radiator Valves.

I want to delete one of them via the iPhone-app: "Administrate my Home -> Click the Room -> Click the Valve -> Delete". And the Valve is gone from the Room.

When going back to Administrate my Home I still see two ("2") Valves for the room. However, if I click the room only one Valve en pressent.

What to do?

Thanks in advance.