Nick Foles and the Eagles appear to have been lined up in illegal formation on the awesome fourth down trick play that put them up 22-12. NESN/ESPN commentator Matt Chatham diagrammed:
NFL rules stipulate that you need to have seven players on the line of scrimmage, and in this grab they certainly appear to only have six.
Here is video of the play, which confirms that Foles was not on the line at the snap:
While the Patriots have benefitted from who knows how many calls or missed calls in their 18-year dynastic run, if the Eagles hold on for the victory we can expect this to be a point of conversation.