Nexus 7 users had been complaining about issues with the GPS and now it looks like multitouch has been added to that list. Similar to the GPS complaints, it looks like those users complaining from issues with multitouch are telling the same story. Basically, reports are citing issues with pinch to zoom in apps like Maps and the keyboard registering double taps on letters.
Judging from a scan of the Product Forums, this is an issue that Google is aware of. In fact, it was said that "the Android team is aware of this issue and investigating." The issue seems to apply to some, but not others. While we cannot necessarily say it is a widespread issue, it does seem to have affected the same person on multiple tablets. Simply put, exchanging your current Nexus 7 for new may or may not resolve the issue.
It seems this issue doesn't necessarily start from first boot. User reports have said their tablet appeared good initially and got progressively worse with time. Some users have been trying some of the multitouch test apps to find their Nexus 7 shows many ghost taps. Perhaps more to the point though, the same Google employee that acknowledged the Android team was working on the issue had also suggested booting to safe mode or even restoring to original to try and isolate the issue.
The reasoning here is that if this is related to an app you have installed it should not happen in safe mode (or after a fresh restore). Of course, this is more just a way to try and resolve the issue and not a solution. With that in mind, it seems majority of the users that have tried the safe mode route have returned to the forums with word of the issue remaining. Basically, it looks like this is an issue with the Nexus 7 and not a complication with a third party app.
At this time Google has yet to offer a timeline as to when this may be fixed, but it is looking like this will all be fixable with an update. The catch is, we hope that Google is able to isolate the issue and get that update rolled out sooner rather than later.