Are You sure you dont have any issues? because the subtitles work fine until you watch the movie again and realize there is no subtitle because it wasnt actually saved in the same folder.
And are your movies shared from a windows pc? Anyway i havent tried it again to see if this issue was fixed recently. It can be a lot of things (windows version, wifi settings, permission seyyings etc etc)
But like i said its working fine now but im using nfs
not using windows pc, i have a router (RT-AC68U) sharing a hard drive., currently using wired lan, but i had no problems with wifi before i switched