Yup I see the same thing... I learned more 
Yes Open a ticket BUT... I suspect support is going to tell you this about the API
Kibana Fleet APIs
This functionality is in technical preview and may be changed or removed in a future release. Elastic will apply best effort to fix any issues, but features in technical preview are not subject to the support SLA of official GA features.
But I would submit it anyways so it shows up as a Bug.
And only Revoke is supported in the UI today not delete so that is supported, I suspect the Delete will come in the future...