The Duke and Duchess of Sussex "stepped back" from the Royal Family in 2020 before their high-profile move to California.
Now living in their Montecito mansion, Meghan and Harry left the UK after a dramatic spell as working royals following their 2018 marriage.
And revelations from a tell-all biography cast a new light on how the former Suits star fitted in when she first met the Duke's friendship group.
Princess Diana's youngest son invited Meghan to join him at Sandringham for a weekend shoot in 2016, according to Tom Bower – journalist and author of 'Revenge: Meghan, Harry and the war between the Windsors'.
Prince Harry and Meghan Markle
PA Features Archive/Press Association Images
Prince Harry was looking forward to 'endless banter'
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Prince Harry 'had not anticipated Meghan's reaction' to how his friends behaved
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The 37-year-old is said to have invited 16 friends, mostly from Eton – where Harry went to school.
The plan was for them to join him for dinner on Friday, followed by a shooting day on Saturday and then lunch on Sunday.
Mr Bower writes that Harry was "looking forward" to "endless banter" with friends but "had not anticipated Meghan's reaction".
To the prince's surprise, when his friends "contravened her woke values", Meghan "challenged every guest".
The investigative journalist adds: "Like other shooting weekends, Harry was looking forward to endless banter, jokes – and a lot of drinking.
"He had not anticipated Meghan's reaction.
Prince Harry invited Meghan Markle to a shooting weekend with his friends
PIROSCHKA VAN DE WOUW
"Their jokes, involving sexism, feminism and transgender people, ricocheted around the living-rooms and dining-rooms.
"Without hesitation, Meghan challenged every guest whose conversation contravened her values. She lacked any sense of humour.
"Driving home after Sunday lunch, the texts pinged between the cars: 'OMG, what about HER?' said one. 'Harry must be f***ing nuts!'"
Mr Bower, in the book being serialised by The Times, also claims Meghan clashed a second time with Harry's friends, this time during a trip to Jamaica for the wedding of Tom 'Skippy' Inskip in March 2017.
The Duke and Duchess of Sussex joined 40 guests for the three-day celebrations in Montego Bay, where Meghan "refused to engage with Harry's friends" and instead made "remarks about the food".
In the same book, Mr Bower writes about how Meghan was asked to appear on the cover of Vanity Fair's September 2017 issue.
The magazine ran with the headline 'Wild About Harry' on its front page – choosing to focus on the former Suits star's relationship with the prince, rather than her charity work.
When pre-publication copies were sent to the Palace, Meghan is said to have reacted "hysterically" as she "furiously" phoned her PR firm.
In the 2017 culture magazine, Meghan said: "I'm sure there will be a time when we will have to come forward and present ourselves and have stories to tell, but I hope what people will understand is that this is our time.
"This is for us. It's part of what makes it so special, that it's just ours. But we're happy.
"Personally, I love a great love story."
Mr Bower reports that Meghan was livid when Vanity Fair chose to lead their feature on these quotes, rather than focus on their philanthropy.