I'm translating file ojs/plugins/pubIds/doi/locale/fr_CA/locale.xml and I just realized that the english equivalent file contain 2 keys with the same text label:
<message key="plugins.pubIds.doi.editor.customSuffixMissing">The DOI cannot be assigned because the custom suffix is missing.</message>
<message key="plugins.pubIds.doi.editor.assignDoi.emptySuffix">The DOI cannot be assigned because the custom suffix is missing.</message>
Is this an error ?
The first key is about the missing custom DOI suffix, the second one is, I guess, more general in indicating that there is a missing suffix. Anyhow, this is how I translated it for fr_CA.