While it is easy enough to pop the glass panel off the iMac for cleaning I would actually caution against it. The panel is a dust magnet. Apple does this in dust-controlled rooms with silicon rollers as you can
Maserati's comments were absolutely not helpful.
That's the first time I've ever seen that. It's impossible to tell from the picture which is also a little blurry, but are those spots on the panel itself under the glass? I'm assuming you already tried cleaning the glass in that area.
If so it's definitely a defect, or dirt and you should send it in to Apple for service.
Thanks for sharing.
It looks like there is yet another flaw to look out for with the new iMacs. I wonder how widespread it is. Looks like internal electrical smoke. I doubt external smoke would get in like that. Was there a burning or acrid smell accompanying the black blotches?
The 27" imac screen is a complete disaster, flickering, yellow tint and now this. These are NOT premium monitors they're junk.