I have never had a problem like that. My 52525 has been on for 13231 hours and had two lamp replacements. I wouldn't know what a light engine problem would look like.
The only problems I have had were when searching for digital channels the TV shuts itself off before its finished, The HDMI picture is shifted down a half inch to an inch on my cable box when compared to Component (could be the box), the did you replace the lamp question pops up for no reason after I turn the TV on sometimes, and not quite in the middle of the screen a line appears every once in a while for like a second its like the image coming of the mirror didn't line up.
The only problems I have had were when searching for digital channels the TV shuts itself off before its finished, The HDMI picture is shifted down a half inch to an inch on my cable box when compared to Component (could be the box), the did you replace the lamp question pops up for no reason after I turn the TV on sometimes, and not quite in the middle of the screen a line appears every once in a while for like a second its like the image coming of the mirror didn't line up.