"Dark Corners" on new Sony Model KDL60EX645 - possible generic issue

Just wanted to let the forum community know that I may have encountered a possible generic (I would call minor) flaw with the new 60" Sony LED line of TVs. I recently bought a new KDL60EX645 and discovered that it exhibited a small "dark area" angling up diagonally out of both the left and right lower corners of the screen, otherwise the set was very good. The dark spots are barely noticeable during "normal" viewing with varied colored background/images, but are easily spotted against a white, yellow, light blue, light grey, etc screen. It's almost like the opposite of flash-lighting. It almost seems like a shadow or smudge trapped underneath the outer screen.

Anyway, I decided to exchange it for another unit, and was able to swap to a different tv with a serial number separated by over 9000 and built about two months apart. The replacement set has the EXACT same shadow/dark spots in the same locations. I can now say that this model Sony has a generic flaw, or I just happen to be a victim of quite a coincidence.

I just wanted to get this info out, so that anyone else considering this particular model can have a "heads-up". I would welcome anyone else to share their experience if the too own or purchase this model. I would also welcome any opinion as to what may be the cause of this condition. The dark spots are present on every input and present with or without a signal. No picture adjustments affect them either, but the backlight and contrast will "interact" so to speak with the dark spots, altering their prominence slightly, but it's just masking the effect not actually changing anything.

At this point I will likely keep the set, because besides for this issue everything else is quite good. No significant/noticible banding or DSE, no flash-lighting or clouds, good picture quality, etc.

Thanks for listening!

Update...

After spending more time with the set, I can add a few fresh observations:

I don't think that it's a "reverse flashlight" because the same lower corners do have moderate flash-lighting in a dark room and dark onscreen image. I think it's a mechanical issue in the way the various screens and panel interacts in the lower corners. If I push/pull on the parts of the frame/bezel near the corners, I seem to be able to very briefly alter the magnitude of the darkness/size of spot. It's as if the screen is contourted in some sort of way that a shadow is being cast and appears on screen.

I am kind of surprised this is not being noticed/reported in other large (60" plus) Sony's

Update 2:

Exchanged the second set for a third, attempting to eliminate what became an unacceptable backlight bleed.

Anyway the third set (serial number about halfway between the first two) has the EXACT same dark spots in the lower corners. Unfortunately set three also has backlight bleed.

Sony's quality control must be very, very poor

Still like the picture though

Update 3:

Exchanged the third set for a fourth, in a continuing attempt to eliminate unacceptable backlight bleed.

Anyway the fourth set (serial number one off from TV 1) has the EXACT same dark spots in the lower corners.

BUT thankfully the backlight bleed although there is minor an I can live with it

Anyone looking to buy this TV needs to stay above a serial number of 501000 and and past a September build date or risk nasty flashlights

I am sure that the LED's are present in the corners...

I am now convinced after having 4 of the exact same tv's in my living room, that it is a shadow or some other sort of light distortion caused my how everything is assembled.

It's important to note that these two lower corner "shadows" are VERY subtle and do not spoil normal viewing. If you are watching the TV normally, with your eyes focused primarily center screen, you won't even notice it.
Basically you have to be looking directly at the corner when a light colored background is present.

Just to be fair, this is a very good tv for the money. I have decided to keep my current unit, and as I had mentioned the "dark spots" are not significant in normal viewing.