Besides the surprising fact that Japanese gamers actually bought a game for the Xbox 360 (considering the low popularity of the console in the country), it sounds like those who chose to support this version of the game are facing some unexpected lag problems when they play the game online.
The official Persona blog has been updated with an apology from Atlus stating that they are investigating the problem and are promising to provide an immediate follow up report when the problem is identified. Until that time, Atlus has suggested that gamers change their network settings to say “Good Connection Only” instead of “Same Area Only.” It is not yet known if this problem will be fixed and patched before the North American release of the game on August 7th.