Streaming a zip folder to S3 from Lambda

Hi. I've got an automation set up that backs up our Jira instance and uploads it to an S3 bucket. I recently changed the credentials used by the automation and it stopped working. I tried to fix it and even went back to the old credentials but get this error when trying to upload to S3: error: An HTTP Client raised an unhandled exception: sequence item 0: expected str instance, bytes found The error coming from : s3_client.upload_fileobj(backup_data, bucket_name, 'backups/' + s3_object_key). The code works fine locally but not on the Lambda.

Additionally, I once had this same issue, but had no fix for it. after a few days the error didn't come up. I can upload a json file to S3 via the Lambda function but this Zip folder. I've been going around in circles to try and fix this. I've attempted to update the layer as well to include the latest version of packages. Any help on this is greatly appreciated.