gsutil cp gs://source_file s3://destination_file does not work on compose produced files

When copying file(s) from google cloud storage directly to amazon simple storage, the upload stalls indefinitely without a sign of life...

I am on gsutil version: 4.34 on a mac and on Google's Debian GNU/Linux 9 (stretch) Compute Engine VM, this issue has been true since at least 4.31

I am trying to upload files which are ~300mb
This does not seem to work via rsync either.

Please advise.