Prince Harry's absence at his grandfather Prince Philip's memorial service remains a hot topic. As many believe his nonappearance has something to do with security concerns, a royal expert thinks he may have other reasons.

Royal expert and author Robert Jobson believes there's a real reason behind Prince Harry and Meghan Markle's refusal to return to the U.K. and it's not about the former's issue against Home Office about his family's security. So, what stops the Duke of Sussex from visiting his home country?

Express noted that the Sussexes had confirmed their appearance at the Invictus Games in the Netherlands this weekend. With that said, Jobson revealed the father-of-two's decision to snub his grandfather's memorial in the U.K. but to Hague had nothing to do with safety concerns.

Instead, it may have stemmed from feeling wanted. He told The Mirror Prince Harry would be notable n Hague. As an Afghanistan veteran, his past and present brothers and sisters in arms would praise him for "giving back to the armed forces and not forgetting them."

However, it will not be the same when he visits the U.K. with his own family, and it may have something to do with his upcoming book. Jobson continued his book might reveal his real relationship with Camilla, Duchess of Cornwall.

The latter is set to become the future Queen Consort, as confirmed by Queen Elizabeth II herself in February, which might be the real reason why he chose to stay away.

Rumors have it Prince Harry would target his stepmother in his memoir. Royal author Tina Brown revealed he couldn't stand his father's second wife and didn't even want her to be the next queen.

He might go after her and even Prince Charles, as Brown claimed he had yet to make peace with her. For starters, Prince Charles and Camilla went public with their relationship in the early 2000s.

Although it was already several years after Princess Diana's death, Prince William and Prince Harry were not seen with her in public until 2001. Meghan Markle's husband's first introduction to Camilla was said to be "awkward and tense."

He was only 13 at the time, missing his mom and wasn't in the right position to defend her. Though royal biographer Penny Junor revealed in her book "Prince William: Born to be King" that their relationship today is warm, it wasn't like that back then.

The two princes might have found it hard to understand their dad's new romance. Royal author and former Vanity Fair Editor Tina Brown also wrote in her new book, "The Palace Papers," Prince Harry "unnerved Camilla."