Are Alternate Translations Errors?
Most languages allow for different word choices to express equivalent (or near equivalent) meaning. In English we refer to different word that mean the same thing as synonyms.
If a translator uses a synonymous term in a translation, a term that might not correspond with the word choice preference of a third party reviewer, is the choice an error? Most reasonable people would agree that such instances are not errors.
Bilingual Glossaries and Terminology Lists
Translation clients have the option of providing a glossary of preferred terminology at the beginning of a project. In the absence of a glossary translators will perform research or use terms consistent with their own linguistic experience over the course of a translation project. In this way translation clients buy the judgment of professional translators, people who work with language professionally on a daily basis.
Actual Translation Errors
Actual translation errors can occur despite processes to guard against them. We cannot completely remove the possibility of error from human activity. In the vast majority of cases alternate translations selected by translators are questioned as mistakes, often by reviewers whose language skills are not at the level of the original translators. Amateurs critiquing professionals is a recipe for conflict, especially when amateur linguists are also paying clients.
As professional translators we do the best with the things we can control, and then do our best to manage the effects of things we cannot control.