Poetry fails with "Retrieved digest for package not in poetry.lock metadata"

We're trying to merge and old branch in a project and when trying to build a docker image, poetry seems to fail for some reason that I don't understand.

I'm not very familiar with poetry, as I've only used requirements.txt for dependencies up to now, so I'm fumbling a bit on what's going on.

The error that I'm getting (part of the playbook that builds the image on the server) is this:

       "Installing dependencies from lock file",
        "",
        "Package operations: 16 installs, 14 updates, 0 removals",
        "",
        "  • Updating importlib-metadata (4.8.3 -> 2.0.0)",
        "  • Updating pyparsing (3.0.6 -> 2.4.7)",
        "  • Updating six (1.16.0 -> 1.15.0)",
        "",
        "  RuntimeError",
        "",
        "  Retrieved digest for link six-1.15.0.tar.gz(sha256:30639c035cdb23534cd4aa2dd52c3bf48f06e5f4a941509c8bafd8ce11080259) not in poetry.lock metadata ['30639c035cdb23534cd4aa2dd52c3bf48f06e5f4a941509c8bafd8ce11080259', '8b74bedcbbbaca38ff6d7491d76f2b06b3592611af620f8426e82dddb04a5ced']",
        "",
        "  at /usr/local/lib/python3.7/dist-packages/poetry/installation/chooser.py:115 in _get_links",
        "      111│ ",
        "      112│         if links and not selected_links:",
        "      113│             raise RuntimeError(",
        "      114│                 \"Retrieved digest for link {}({}) not in poetry.lock metadata {}\".format(",
        "    → 115│                     link.filename, h, hashes",
        "      116│                 )",
        "      117│             )",
        "      118│ ",
        "      119│         return selected_links",
        "",
        "",
        "  RuntimeError",
        "",
        "  Retrieved digest for link pyparsing-2.4.7.tar.gz(sha256:c203ec8783bf771a155b207279b9bccb8dea02d8f0c9e5f8ead507bc3246ecc1) not in poetry.lock metadata ['c203ec8783bf771a155b207279b9bccb8dea02d8f0c9e5f8ead507bc3246ecc1', 'ef9d7589ef3c200abe66653d3f1ab1033c3c419ae9b9bdb1240a85b024efc88b']",
        "",
        "  at /usr/local/lib/python3.7/dist-packages/poetry/installation/chooser.py:115 in _get_links",
        "      111│ ",
        "      112│         if links and not selected_links:",
        "      113│             raise RuntimeError(",
        "      114│                 \"Retrieved digest for link {}({}) not in poetry.lock metadata {}\".format(",
        "    → 115│                     link.filename, h, hashes",
        "      116│                 )",
        "      117│             )",
        "      118│ ",
        "      119│         return selected_links",
        "",
        "",
        "  RuntimeError",
        "",
        "  Retrieved digest for link importlib_metadata-2.0.0.tar.gz(sha256:77a540690e24b0305878c37ffd421785a6f7e53c8b5720d211b211de8d0e95da) not in poetry.lock metadata ['77a540690e24b0305878c37ffd421785a6f7e53c8b5720d211b211de8d0e95da', 'cefa1a2f919b866c5beb7c9f7b0ebb4061f30a8a9bf16d609b000e2dfaceb9c3']",
        "",
        "  at /usr/local/lib/python3.7/dist-packages/poetry/installation/chooser.py:115 in _get_links",
        "      111│ ",
        "      112│         if links and not selected_links:",
        "      113│             raise RuntimeError(",
        "      114│                 \"Retrieved digest for link {}({}) not in poetry.lock metadata {}\".format(",
        "    → 115│                     link.filename, h, hashes",
        "      116│                 )",
        "      117│             )",
        "      118│ ",
        "      119│         return selected_links"
    ]
}

If you notice, for all 3 packages, the retrieved digest is actually in the list of digests of the metadata section of the poetry lock file. Our guess is that maybe this lock file was generated by an older version of poetry and is no longer valid. Maybe a hashing method should be mentioned (for example the retrieved digest is sha256, but no method is specified on the ones that are compared with it)? Another curious thing is that poetry is not installed inside the dockerfile, but seems to reach that point, nevetheless, and I'm really curious how this can happen.

Any insight would be greatly appreciated (and any link with more information, even)!

Thanks a lot for your time! (Feel free to ask for more information if this seems inadequate to you!)

Cheers!