G.I. Joe: Retaliation: Of 9 months from June 2012 to March 2013, so the film could be converted to 3D & more scenes could be shot with Channing Tatum, after the main complaints from test screenings were that the film wasn't going to be in 3D and audiences weren't happy with how little time was spent on the development of the relationship between Duke & Roadblock before Duke's death. It was also anounced a month before the films release, and roughly a week before the toys were due to be released.
Fans were waiting for nearly eight years for a sequel to Robert Rodriguez's Sin City, and it wasn't until 2012 that the sequel finally entered production, and it was released in late 2014.
A minor slip happened with the DVD debut of Terminator 2: Judgment Day (originally scheduled to be released on none other than Judgment Day itself), perhaps owing to the fact that it was literally a revolutionary disc, being the very first dual-layer DVD on the market, and there may have been a few bugs to work out that took a bit longer than anticipated.