As established in the question, Do authors who translate their own works tend to do accurate translations?, authors who translate their work often emphasize different elements and they do not always give the most 'accurate' translation, from a purely objective perspective. In this question, it is observed that other translations of the works are made, in addition to the authors.
From this it is clear, that there could in some cases be significant variance between the original and the translated languages' editions. When analyzing the work, which version should be taken as the definitive edition, given that they were both produced by the author? What about when neither is published explicitly as a translation of the other?