She also suggested that when she had felt suicidal, the institution had failed to help her.
However, Harry insisted: “I would never blindside my grandmother, I have too much respect for her.”
The Queen reacted to the interview by insisting that the couple’s allegations would be “taken very seriously”.
“The issues raised, particularly that of race, are concerning,” she said.
“Whilst some recollections may vary, they are taken very seriously and will be addressed by the family privately.”
Finding Freedom, published last northern summer, will be republished in paperback on August 31 with an epilogue summarising the events of the last two years.
In an interview to promote the new edition, Scobie claimed that one of the lessons the Sussexes had learnt was to prioritise their mental health and keep “some of the toxicity” at an arm’s – and ocean’s – length.
He also told People magazine that as their period of shared parental leave drew to a close two months after the birth of daughter Lilibet, the couple were entering a new “era of visibility”.
He said: “They’re a couple who do very well in those moments of human interaction. They need to be on the ground. They say that the proof is in the pudding, and what we are about to see is that pudding.”
His comments raise the prospect that the Sussexes will take part in royal-style walkabouts on US soil.
The epilogue is expected to cover the Sussexes’ interview with Winfrey, the bullying allegations made against the Duchess by royal staff, which she denies, and the Prince Philip’s death.
It is also likely to touch upon the couple’s multimillion-pound deals with Netflix and Spotify and the Queen’s decision to strip them of all royal patronages earlier this year.
Meghan has insisted that they did not collaborate with the authors.
A witness statement lodged with the court on her behalf suggested the book was full of mistakes.
Buckingham Palace declined to comment.