API Endpoints: Update Metadata For a Dataset / Edit Dataset Metadata

What steps does it take to reproduce the issue?
It needs a published dataset.
The 2 endpoints for updating the metadata fail:
/api/datasets/:persistentId/versions/:latest?persistentId=$PERSISTENT_IDENTIFIER results in a
400, {"status":"ERROR","message":"Only the :draft version can be updated"}

/api/datasets/:persistentId/editMetadata/?persistentId=$PERSISTENT_IDENTIFIER
OR
api/datasets/:persistentId/editMetadata/?persistentId=doi:10.5072/FK2/BCCP9Z&replace=true
result in responses with status code 500.

• When does this issue occur?
  All the time, for published datasets, but it the endpoint for drafts works

• Which page(s) does it occurs on?
  demo.dataverse.org

• What happens?

• To whom does it occur (all users, curators, superusers)?
  me the developer

• What did you expect to happen?
  A 200, with updated metadata

Which version of Dataverse are you using?
v. 5.12.1 build 1122-cf90431

Any related open or closed issues to this bug report?

Screenshots:

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Start by reproducing the two metadata-update requests against a published dataset on demo.dataverse.org, comparing them with the working draft endpoint. Trace the API entry points for /api/datasets/:persistentId/versions/:latest and /editMetadata, then add coverage for published datasets; done means both requests return 200 with updated metadata.