When updating a service via API PUT method, the "value" to be updated becomes null

When I update a service (hook here) remotely using your API:
r = requests.put(url, data = data, auth = auth)

Data being:
type=POST&URL=https%3A%2F%2F4062ecfc-ngrok-com-48trlhsnt04o%2Erunscope%2Enet%2Fintake%2Fwebhook%2Fbitbucket%3Fapi_key%3Dapikey_2

The response I get is:
r = {"id": 2874020, "service": {"fields": [

], "type": "POST"}}"

--> Why is teh value not being updated please?
If it's a bug to be fixed on your side, I will be forced to make DELETE + CREATE instead.
If not, could you please indicate what I should do better?

Thanks a lot for your help,
Adrien