Prince Harry reportedly snubbed a dinner invite with Charles and William at Balmoral after Meghan was banned from joining the royals on the day the Queen died.
The Duke of Sussex insisted Meghan join him, before Charles called to say it was "not appropriate", sources claim.
It is understood Charles believed saying goodbye to Her Majesty should be restricted to the closest family as Kate, now Princess of Wales did not attend.
The dispute is said to have delayed his arrival in Scotland as he missed an RAF flight taken by his brother William, Prince Andrew and Prince Edward.
Harry was reportedly told to make his own travel arrangements and eventually landed at Aberdeen without the Duchess of Sussex at 6:35pm, just moments after the Queen's death was publicly announced.
He also reportedly declined to dine with the King, Queen Consort and Prince William that evening, reports the Sun.
A source claimed Harry was "furious" and his refusal to dine with his father and brother was seen as a "big snub".
It comes after reports Charles insisted on meeting Harry and Meghan before their audience with the ailing sovereign, according to new royal book The New Royals: Queen Elizabeth’s Legacy and the Future of the Crown by Katie Nichols.
It is claimed the Sussexes were late for the awkward chat and Charles had just 15 minutes with the jet-setting pair before they had to leave for the Royal Maundy Service at Windsor Castle.
While it is reported father and son "greeted each other warmly" there were still moments of tension which left the then- Duchess of Cornwall lost for words.
Camilla, who is now Queen Consort, was reportedly stunned when the Prince, 38, suggested an impartial third party be there to keep the peace, reports Vanity Fair in an extract from the royal expert's book.
“Harry went in with hugs and the best of intentions and said he wanted to clear the air,” a family friend said.
“He actually suggested that they use a mediator to try and sort things out, which had Charles somewhat bemused and Camilla spluttering into her tea.
"She told Harry it was ridiculous and that they were a family and would sort it out between themselves.”
Kensington Palace and representatives for the Duke and Duchess of Sussex have been approached for a comment.
