Dear support team!
The bug still exists after several updates. I use russian language as video filenames. When i check “Replace filenames with library titles” the filenames are displayed in english but sorted in original filename (russian). When I uncheck “Replace filenames with library titles” movies are displayed and sorted in english. The problem was appeared maybe 8-10 (or more) updates ago. Before that, filenames was displayed correctly (in russian). I hope you will fix it!
Do you know if this is unique to OSMC? It sounds like a Kodi issue and you may find an answer on Kodi forums.
If not, we would need to know where you get your movie titles from.