An insider told royal expert Quentin Letts that the 93-year-old "does not want to talk about the Sussexes."
People spending time with the Queen were allegedly told not to mention the Duke and Duchess of Sussex.
Letts tweeted on Friday: “Friend of an acquaintance was about to go riding with HMQ.
"Was given v firm advice 'Talk about anything except one subject.' Brexit? 'No, The Sussexes.'"
According toExpress, there have been reports of tension within the royal family after her Majesty was left "deeply disappointed" by the royal couple's snub of her invitation to their Scottish Balmoral Castle residence recently.
Instead, the Duchess travelled to New York to watch best friend Serena Williams compete in the US Open final.
As a result, the royal couple - who live in Frogmore Cottage in Windsor - skipped the Queen's invitation to the Highland games.
WATCH: Prince Harry breaks tradition by shutting own car door
Furthermore, several sources told the publication that the Queen is unimpressed with how the Sussex royals have conducted themselves since their royal wedding last year.
Her Royal Highness is "baffled" by Harry and Meghan's consistent PR blunders.
Their refurbishment of Frogmore Cottage prior to the birth of their son Archie Harrison Mountbatten-Windsor reportedly cost taxpayers $4.4 million.
The Duke and Duchess of Sussex also faced public criticism after chartering a private jet to Ibiza and Nice in a matter of days, with some claiming it seemed to contradict their stance on protecting the environment in Meghan's Vogue September edit.
Queen Elizabeth is reportedly refusing to talk about Meghan Markle and Prince Harry on her Balmoral trip.
In other news, Meghan's maternity leave officially ended this month, with the former Suits actress attending her first official royal engagement post giving birth tobaby Archiein May.
The Duchess stepped out with close friend andfashion designer Misha Nonooon Thursday, September 12, for the launch of their women's workwear collection.
The collaboration will benefit charitySmart Works, an organisation that seeks to help women find employment by providing interview training and professional attire for job interviews.
For more royals news, pick up a copy of this month's New Idea Royals.