The third party software was doing a mixture of writing (uploading), and reading (to verify contents had been uploaded). It was continually trying to upload a 1

The third party software was doing a mixture of writing (uploading), and reading (to verify contents had been uploaded). It was continually trying to upload a 1 GB file for well over 12 hours. It's been a long time since this happened so I don't recall the exact figures, but I remember having some 4 or 5 figure charge from AWS. I think the third party software was just bad at handling large single file uploads over residential internet.