In our production jenkins server I can see a lot of exceptions about web hook automatic registration.
The issue happens only when try to update an existing the web hook. The issue does not happens when register a new one.
In update I got a 403. The reason is why it get the list of web hooks for each repository and register using the path specific for each one repository but try to update using the path of team. This cause the issue because the build user is not an administrator of the team. Only an administrator of the team could add or update webhook inherited by all repositories.
For security reason the build user can only manager repository.

In short actually the cloud api client to retrieve the list of web hooks and register new ones uses REST path specific for repository instead to update use the team REST API path.