Intel's woes with the Cougar Point Sandy Bridge chipset are well known at this point. The issue boils down to a flaw in the P67 chipset that will result in degraded IO performance over time. The flaw could eventually lead to failure of the SATA ports the chipset controls. Intel has previously told its partners to pull boards with affected chipsets from the market and to cease sales.
Intel has now offered up new detail on the issue with the 6 series chipset that will allow its partners to resume shipping systems that aren't affected by the issue. That means that the affected mainboards will ship only if the machines are configured in a manner that will not be affected by the chipset problem, meaning no drives connected to the SATA ports controlled by the P67 chipset. Intel says that this move was made at the request of its partners.
The big issue I see that that is that the initial configuration may not be using the affected SATA ports, but if the end-user isn't aware of the issue at purchase and wants to upgrade later the IO flaw in the P67 would be a problem. Intel notes that it is in manufacturing with a new version of the chipset that fixes the problem.