When looking for a movie with filename "13 (2010).avi", the metadata lookup finds "District 13: Ultimatum".
The FAQ tells me that you use TheMovieDB for lookups, yet the first result when querying there returns the correct result:
(this is the correct result: 13)
Curiously, "District 13: Ultimatum" doesn't actually feature until page 2 of the results. Is this a sorting issue? It seems to return result 11 instead of result 1... might just be coincidence though.
I'm slowly working my way through a huge library of files, so I'll post here if I spot any other oddities.