Page refreshing on Firefox when hitting signer url

[treetop1500]

I'm experiencing an odd behavior where in Firefox 66, the page seems to refresh when the signer url is hit or somewhere around that in the process. Chrome and Safari latest versions are working flawlessly.

My method for uploading is below. I'm using a PHP controller to handled signing at the /aws-signer route. I've also tried using the full URL to that route and the problem persists.

My package.json file is require evaporate.js as such "evaporate": "^2.1.4",

function uploadToS3(files,entityId)
        {
            if (isValid(files)) {

                /**
                 * evaporate.js config
                 */
                let evaporateConfig = {
                    signerUrl: "/aws-signer",
                    aws_key: "(my key)",
                    bucket: "(my bucket)",
                    computeContentMd5: true,
                    cryptoMd5Method: function (data) {
                        return AWS.util.crypto.md5(data, 'base64');
                    },
                    cryptoHexEncodedHash256: function (data) {
                        return AWS.util.crypto.sha256(data, 'hex');
                    },
                }

                return Evaporate.create(evaporateConfig)
                    .then(function (evaporate) {

                        evaporate.add(
                            {
                                file: files[0],
                                name: +timestamp+"-"+files[0].name,
                                progress: (progressValue) => updateUploadStatus(progressValue),
                                complete: (_xhr, awsKey) => console.log('Complete!', awsKey),
                            }
                        )
                        .then(function (awsObjectKey) {
                                uploadComplete(awsObjectKey);
                                console.log('File successfully uploaded to:', awsObjectKey);
                            },
                            function (reason) {
                                console.log('File did not upload sucessfully:', reason);
                            });
                    });
            } else {
                uploadError("Invalid File Type");
            }

[treetop1500]

After looking at this on a staging server (the above) was occurring on my localhost, the refresh is happening at various states in the upload process, not just at the signer request.

[jakubzitny]

Can you please provide a full repro? We can have a look at it.