async nuxeo-operation doesn't respect the promise contract

<nuxeo-operation id="publishOp" op="MediaPublish" schemas="*" async></nuxeo-operation>

this.$.publishOp.execute()
                    .then((response) => {
                        this.document = response;
                    }).catch((error) => {
                    console.log(error);
                }).finally(() => {
                    this.$.progress.disabled = true;
                    this.shadowRoot.querySelector('#action').disabled = false;
                });