FIrst of al sorry for my bad english! :)
I am using Plex media Server in a LG Pb690, usually I use the Smartshare of LG instead of Plex app.
My problem is when I use subtitles in a big file movie (20-30Gb) the movie starts buffering all the time, if I play the same file without subtitles I havn´t any problem... really strange.
I haven´t problems with 8-10 Gb movies with subtitles, only with bigger files.
If I use Plex app occurs the same, the movie start without subtitles, I turn on it in the options, and then the movie doesn´t begin to play.
I have another Lg tv (730v) and it plays all movies always well, for that I know that Plex mediar server in my pc is alright.
Any idea of what is happening?