I have driven both and feel the 276 and 296 are very similar day to day driving, but the 296 does have that extra kick at higher revs when you do use all the rev range.
You could try disconnecting the battery, then reconnect and it may do a sort of reset of the DVD or Sat-Nav. But I think it might be worth calling a dealer to see if they have any idea how to fix it, or if it is covered under warranty.