Below problem applies to both Windows 8.x metro App and Web Player. MBC and MBHT is fine since both uses external subtitle filter.
Basically both unable to encode subtitles with Turkish chars. I couldn't find any setting for char. encoding in both 8.1 app and Web Player.
Below is the line 00:05:49,800 --> 00:05:53,901 from attached srt. (Renamed to txt)