The move to have a different date may seem unusual, but Shout Factory may be pushing for one version to sell more of than the other. Curiously, no date has been set for when Season Three will release to home video.
The spoiler filled synopsis can be found after this break:
A resurrected UNICRON has taken over the now-lifeless body of MEGATRON to seek vengeance on the AUTOBOTS and ultimately, the destruction of Cybertron. This formidable enemy forces an unlikely alliance between the AUTOBOTS, DECEPTICONS, PREDAKING and two new Predacons, who come together in an epic battle to help protect their newly restored planet!