I don't get a 'flash', per se, but I do get a 'small' (maybe 2 inch) translucent 'dot' every couple days. It lasts for less than a second and comes in twos and threes -- never in the same spot, thankfully. I'm not at all sure its the TV (70" LG), but it is quite the enigma. I thought I was seeing things until my wife started noticing it, also.
I think you needs to call Ghost Hunters I think your TV is haunted!
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