When Robert does the press conference he says that he was on the island 10 months 3 weeks and 4 days. However Jasper starts as Eleanors security agent right after Roberts plane went down and in one episode in season 2 he says he was with her for 6 months and it had been several months since he stopped being her agent. The time frame doesn't match up.
When Robert returns James Hill gives him the files of his death and the death of his father and calls him Your Majesty. He should have called him Your Highness since Cyrus was still the King.