Yesterday I uoloaded a .mkv file from my pc to my live hub, witch I bought a week ago (to replace my Iomega screemplaydisaster).
When I wanted to see the file the subs stuttered as if the lifehub was working on the background.
Even the playbackoptions were slow (took about 2 sec. before FF or Stop reacted)
Another .mkv file uploaded a week ago had the same problem ( subs were sync but some lines where not shown ore shown for a fraction of a second).
After a restart all went fine.
Used mkvmerge Gui to muxe in the subs.