Creating multiple events using event-bulk-create-jobs fails when unique_id is added

When using the Bulk Create Events API I am able to create multiple events for the same profile.

However, as soon as I add the unique_id property to the event object the request fails with error 500.

Example request body:

{
  "data":{
    "type":"event-bulk-create-job",
    "attributes":{
      "events-bulk-create":{
        "data":[
          {
            "type":"event-bulk-create",
            "attributes":{
              "profile":{
                "data":{
                  "type":"profile",
                  "attributes":{
                    "email":"dev@user.com",
                    "first_name":"Dev",
                    "last_name":"User"
                  }
                }
              },
              "events":{
                "data":[
                  {
                    "type":"event",
                    "attributes":{
                      "unique_id":"test",
                      "properties":{
                        "name":"My event"
                      },
                      "metric":{
                        "data":{
                          "type":"metric",
                          "attributes":{
                            "name":"My event",
                            "service":"api"
                          }
                        }
                      }
                    }
                  }
                ]
              }
            }
          }
        ]
      }
    }
  }
}

Response error

{
  "errors":[
    {
      "id":"4bcdd0f7-f1f2-4e6e-b9d8-ab3415d88b3c",
      "status":500,
      "code":"error",
      "title":"A server error occurred.",
      "detail":"A server error occurred.",
      "source":{
        "pointer":"/data/"
      }
    }
  ]
}