Autodesk Webhook API event dm.folder.deleted doesn't seem to work

Question

I have made several tests with Autodesk's Webhook API and I cannot figure out what the dm.folder.deleted event does (https://aps.autodesk.com/en/docs/webhooks/v1/reference/events/data_management_events/dm.folder.deleted/).

I have registered the Webhook with the POST request as documented on a sample directory in Autodesk Construction Cloud:

curl -X 'POST'\
     -v 'https://developer.api.autodesk.com/webhooks/v1/systems/data/events/dm.folder.deleted/hooks'\
     -H 'Content-Type: application/json'\
     -H 'authorization: Bearer bNU4P0trbQKNSzxWksLPTzSbbmUz'\
     -d '{
            "callbackUrl": "http://bf067e05.ngrok.io/callback",
            "scope": {
                "folder": "urn:adsk.wipprod:fs.folder:co.s424tpjyS_yYBs5ozch94g"
            },
            "hookAttribute": {
                "something": 34
            }
        }'

In my eyes there are two possible triggers for that Webhook:

• When a folder is deleted inside the folder with the registered hook.
• When the folder itself is deleted.

Both cases won't trigger my callback URL.

Just to be sure that I have not made any setup mistakes: I have also registered the dm.folder.modified event and this one triggers if I create/rename/delete a folder inside the target folder.

I have also fetched all the registered webhooks and can see that the dm.folder.deleted was correctly applied to the desired folder.

Is there another action required which triggers dm.folder.deleted or is it just not working?