With the API endpoint when you create a previously defined event definition that was deleted, we get this error: OBJECT_ALREADY_EXISTS even if the definition is not listed (either when looking at the web UI OR using the event definition query API).
I realised that the web UI append a _v2, _v3 and so on to the event definition names.
So how can it ever by possible to use the API to completely delete an event definition or verify if the name has already been taken in the past? This behaviour makes impossible to use the API in the context of stand alone applications!