Hi, I would like to report to all that I figured out the solution.
Turn of uPnP port forwarding on the NAS where you are playing your video from. Or any device that enables uPnP port forwarding if this is your symptom. Surprisingly, the WD myCloud does not seem to affect it even if uPnP port forwarding is enabled so that you can log on to that device through the internet.
In short, it is certain devices that cause this problem. In my case, it was the NAS TS-212P running QTS 4.0.7. Once I turned it off, the WDTVLive worked normally as before.
