I have moved to a new house and sometimes we hear this sound that can be found in the link. It is likely happening when the boiler is running. It happens in random times. One Plummer has looked at the video and started commenting about trapped air but then when he saw the reaction of the radiator when I slightly turned the valve either way, he told me that it is likely the in-feed and the return pipe connection are made incorrectly and the flow is in the wrong direction where the water pressure is getting the valve needle to bounce inside the valve head and making the noise. I would like to double check with you here and confirm if it is the case. If not, what is your take on the cause of this?