Webhook notifications gives wrong URL to custom API


We are currently assisting a third party vendor with implementing webhook notifications in Business Central. We are able to create a webhook subscription to our custom API, and the third party vendor is notified of changes in the published resource as expected, but Business Central does not give correct URL in the notification message

Business Central gives the URL as api/v1.0/companies(<companyId>)/<resource>

But this is a custom API, and Business Central should give the URL as api/<apiPublisher>/<apiGroup>/v1.0/companies(<companyId>)/<resource>

It should be noted that this is an on-premise installation version 16.0.11233.12061

Has anybody else experienced this when working with APIs and webhooks?