Seth Weintraub of 9to5Mac translated the original French story:
The source blames a welding process for the delays, which would push the iMacs into 2013. The new iMacs also have a redesigned display that features a new thinner lamination process.
Earlier this year, I heard separately that one of the reasons the third-generation iPad didn’t get a laminated display was because of manufacturing challenges at such a large scale. There are a few recent 10-inch tablets which do have a laminated display, but the fourth-generation iPad still does not. However, these other tablets aren’t selling at anywhere near the same rate as the iPad, which means that the challenges of mass-producing large laminated panels might not apply as much.
It appears to be a similar story with the iMac.