So the actual app_APP_UUID_01.tar.gz.enc was created prior to the multiparty copy attempt. Also it seems first two parts were copied fine and suddenly the S3 object cannot be found anymore for a brief period? Is this easily reproducible or more of an occasional hiccup?
@dsp76 thanks, will adjust the code accordingly. https://docs.ionos.com/cloud/managed-services/s3-object-storage/endpoints says it is a "contract owned" endpoint and it's the future