I think you'll probably need the user's input command as well to investigate
this. The deposit client can generate a uuid to use as external identifier (if none
is provided).

And that might be the origin of the noise here (thus why i was reticent on that
uuid generation in the first place ¯\_(ツ)_/¯). Hopefully, i'm wrong and that's not
the issue.

Here is the command:

swh deposit upload --username ipol --password "mypassword" \
                   --archive mlheIPOL.tgz \
                   --collection 'ipol' \
                   --metadata metadata_test1.xml

in https://forge.softwareheritage.org/source/swh-deposit/browse/master/swh/deposit/cli/client.py$187
Before verifying if a metadata file exists there is a slug that is generated (if it is not given in param)
Normally the slug is the external-identifier, which should be passed in the metadata file.

I'm not sure, but maybe the origin is created with the concatenation of the client-url and slug, instead of the actual url in the metadata.

Continuing my investigation...

The slug must be added to params.
Origin is created from the concatenation of provider_url+slug.

See P662 for client configuration.

Users of the deposit API command line client must add a --slug command line option to avoid the creation of a uuid.
For IPOL, we agreed on the following:
SWH configuration side: provider_url = https://doi.org/10.5201/
slug on the command line = rest of the url, that is, for example, ipol.2018.236