I recently purchased an 60PN5000 LG Plasma, which is connected as a monitor to my HK AVR254. The HDMI video devices I use on that AVR are a ROKU3 and Sony Blu Ray player with all the usual internet widgets. We do a lot of movie watching, and I've only seen this a couple of times. Certain movies cause the TV to power toggle (to off), and this is the first time I've really got a chance to investigate.
So, we were watching previews for Amazing Spiderman 2 and Muppets Most Wanted. Spiderman did fine, but when I went to play the muppets via youtube on the ROKU, there is a specific scene where Kermit's look-alike hops over a wall and there are two flashes of lightning and BOOM, TV shuts down. This is repeatable EVERY time! Just for grins, I played the same preview from a 3rd party youtube app and the exact same thing happened.
I switched to my BluRay player and brought up youtube on there...you guessed it, exactly the same occurrence at the exact same spot in the preview. I loaded the Amazon Video app and played the preview from there...yup, same thing.
I switched back to the Roku and brought up Amazon video on there and it happened again, as expected.
I'm thinking two possibilities. One, there is some sort of control bit coming through the HDMI from the video source, or, Two, somehow the fast lightning flashes are causing the TV to shut down.
The video in question is called "Muppets Most Wanted Official Trailer", if anyone else with an LG TV wants to give it a try.
I'm lost on this one.