React Native Fetch on Android will not pass options

I can't seem to get Android to pass any options when it works fine on iOS. It appears to go to the endpoint and drop the method, headers and body. I don't know for sure because when I added some of the code I mention below to debug, it works.

let data = JSON.stringify({
    appKeyLookup: CONSTANTS.APP_KEY_LOOKUP,
    username: username,
    password: password,
});
try {
    let response = await fetch(CONSTANTS.API_URL + 'login/', {
        method: 'POST',
        headers: {
            Accept: 'application/json',
            'Content-Type': 'application/json',
            'Cache-Control': 'no-cache',
        },
        body: data,
    });
    let responseJSON = await response.json();

The really weird thing is, that if I add

const _XHR = GLOBAL.originalXMLHttpRequest ?  GLOBAL.originalXMLHttpRequest : GLOBAL.XMLHttpRequest            
XMLHttpRequest = _XHR

To the entry point and then install the chrome extension Allow-Control-Allow-Origin:*

It works fine. So it seems it has something to do with CORS but I am not sure.

I am on React Native 0.56.0