File uploaded to s3 but it doesn't open(corrupted)

I’ve the following ts code that submit a file came from GraphQL API to my AWS S3 bucket. it works perfectly when I run the project using http lib, but when I run it using sls offline start or from aws lambda function it uploads the file but it doesn’t open(like a damaged file) - except text files
the code:

const fileStream = data.createReadStream()
const uploadParams = {
                Bucket: 'XXX',
                Key: data.filename,
                Body: fileStream,
                ContentType: data.mimetype,
                ContentEncoding: data.encoding,
                ACL: 'public-read',
const result = await s3.upload(uploadParams).promise()

data object looks like this:

{ filename: '11083626_830419647032756_2338667058698516671_n.jpg',
  mimetype: 'image/jpeg',
  encoding: '7bit',
  createReadStream: [Function: createReadStream] }

After adding this to serverless.yml. It worked in AWS but still doesn’t work with sls offline start:

            - 'multipart/form-data'