PUT request from React through superagent being sent with no content

The method sending the request looks like this:

const updateCompany = ({sessionKey},company) => {
    const tempCompany = company.newCompany;
    console.log("sessionkey:" + sessionKey);
    console.log("check123" + JSON.stringify(tempCompany,getCircularReplacer()));
    const url = createServiceUrl(`api/company/${sessionKey}/${tempCompany.id}`);
    request
        .put(url)
        .send({ Company: tempCompany })
        .end((err, res) => {
            if (res.ok) {
                console.log("Updated OK!")
            }
        });
}

The check123 console.log prints the object I’m trying to send with all the expected values and keys, but for some unknown reason the request going out is completely empty and all I get back from the controller is a 204. I suppose I’m supposed to do something differently here, but I can’t see what.