I found this source that seems to indicate that our current Spanish title is correct.

Yeah, I agree we seem have the correct original es-ES title. The theatrical distributor, trailer and posters all use "The Imitation Game (Descifrando Enigma)". Some subsequent DVD, TV and digital releases also kept the original title. Netflix however uses an alternative title, Descifrando enigma.

It is a common practice in Spain that everyone publishes posters anyway, sometimes motivated by the lousy titles adapted locally. But in a database you must follow a system and avoid arbitrariness. In Wikipedia, this film appears like this. In the absence of another, I am following its criteria to write homogeneous titles, according to its own guidelines (1) & (2). I think it is redundant to include the original title as part of the localized title when it is already reflected in its section. But I am also consulting other sources and it is not clear to me.

If a specific title is used in a theatrical release, then its the official title -- regardless of how we feel about the title. TMDB will follow our own title guidelines, not guidelines set by another site such as Wikipedia.

I balked when I first encounter a title using the Original Title (Translated Title) format, but I've come to accept that it's a common enough practice in Spain. Just like Original Title - Translated Tagline is a common format for German titles. We really have no desire to police official titles.