Despite the warning letter, Thomas recently told DailyMail.com he planned to invite the Duke and Duchess of Sussex to his own wedding in March, when he plans to Wednesday Darlene Blount in Reno or Las Vegas.
The Royal Foundation, which was initially founded by Princes William and Harry and Kate, tackles issues including wildlife and conservation, young people, the armed forces community and mental health.
Last year, it was reported that Markle's personal assistant, Melissa Touabti, was resigning after just six months.
Both the unnamed bodyguard and Ms Cohen worked for Ms Markle and her husband Prince Harry.
According to The Sun, a Scotland Yard (police service responsible for policing most of London) source said: "Unlike someone who has grown up in the Royal Family and has been used to close protection from an early age, having it can be quite constraining". "Even though [Meghan] was a famous actress, she could still do what she wanted in the way of getting around freely".More news: Chelsea desperate to complete signing of 290-goal striker from European giants
The Met could not confirm the bodyguard had quit because they said they do not comment on anyone involved in the bodyguard role. At 1:33 a.m., authorities pulled him over and performed a field sobriety test which confirmed that Thomas was inebriated.
He hoped that despite an estranged relationship between Meghan and his side of the family that his nuptials would bring them closer.
"Just as Meghan encouraged a helping of culinary adventure, so she dramatically changed the contents of Prince Harry's fridge", Morton told the outlet.