github_app_authorization webhook event is not triggered when user revokes App authorization

I’m working on a Github App which is created from Manifest and installed on a Github Enterprise. User also authorize the app and grants it a token. According to documentation (Handling a Revoked Github App Autorization) I should be getting the github_app_authorization  webhook by default when the user revokes the app, but this is not the case. Revoking the authorization never fires the github_app_authorization  webhook event (even under the recent deliveries section i only see the ping events).

Am I missing something in the documentation?

Also, I’ve tried explicitly requesting the  github_app_authorization  in the default_events of the Manifest parameters and I get an error saying  github_app_authorization  is not valid.

It’s possible that event hasn’t been pushed out to GitHub Enterprise yet. Which version of GitHub Enterprise is installed where you’re at?