This has been going on for some time, but I can be watching Netflix or Hulu or a random video through the dedicated Video Player, or even listening to Pandora.
What happens is the video starts to lag a bit and then it just pauses or freezes. The volume indicator will come up too. Usually I can hit the Play button to start it back up but some apps require a complete force stop and reopen.
This happens roughly on a 30 minute interval when the TV is on.
Have you tried rebooting your TV, router or cable modem or all 3? Does it only do this when you are playing videos over the network? I have an x850c and don't have this issue at all. Your issue to me seems network related. Also, is your TV wired into your network or using wireless? Mine is wired in on a gigabit network.