Meghan Markle reportedly fired her nanny who was only days into the role following an "incident".
The Duchess of Sussex and Prince Harry employed a night nurse in 2019 to assist them in developing an evening routine for their now two-year-old son, Archie, while they were still living in the UK.
Royal author Omid Scobie, who co-wrote the favourable Meghan and Harry book Finding Freedom, said there was a mysterious incident on one of the first nights that permanently put the couple off having a night nurse.
Speaking on Britain's A Very Royal Baby: From Cradle to Crown, Scobie said: "Very few people know the real story behind it.
"After Archie's arrival, Harry and Meghan wanted some help to establish a sleep pattern. They hired a night nanny.
"Whilst I can't go into someone else's employment details for legal reasons, it was an incident on one of the first nights that put the couple off from having a night nurse."
It is widely reported Meghan, 39, is close friends with Scobie and leaked information to him for his tell-all book, however the Duchess has disputed this.
The claim comes after a bombshell report by The Times of London in March that alleged Meghan had bullied several staff, which was published days before the Sussexes' Oprah Winfrey interview was set to air.
The former Suits actress was accused of bullying several members of her staff prior to, and after, her 2018 royal wedding.
Buckingham Palace announced at the time its HR team would investigate the claims.
The Times claimed the treatment spanned back to before the couple were engaged in late 2017.
However, speaking in the AppleTV+ documentary, The Me You Can't See, Harry accused "The Firm" of launching a smear campaign.
"Before the Oprah interview had aired, and because of their headlines and the combined effort of the firm and the media to smear her, I was woken in the night to hear Meghan crying into her pillow because she doesn't want to wake me up because I'm already carrying too much," he said.