BTW, I found a wee foreshadowing nugget of press from Elle Magazine, dated 12/10/2018. Regarding the planned departure of Meghan's Private Secretary Samantha Cohen, we have this:
While Cohen was only in the job temporarily, she was well-liked, and Meghan had been "keen" to keep her in the position permanently. But Cohen is ready to move on.
“Sam will be a huge loss,” a source with ties to Meghan told the outlet. The source then suggested Meghan may need a less traditional hire for the role as she carves out her place in the royal family. “Going forward, Meghan might need someone cut from a slightly different cloth to traditional courtiers, who is not a career civil servant or royal insider," the source said. "Meghan needs someone with reserves of energy and patience to help her define her future role."
Cohen had been the Queen's Assistant Private Secretary for several years, and in October of 2017 had resigned in solidarity after her own boss, longtime Private Secretary Christopher Geidt, was forced out of the job by Prince Charles and Prince Andrew. (Geidt, btw, was counseling the Queen to go much harder on Andrew over the Epstein business. In the UK government, the Private Secretaries are equivalent to what Americans think of as a Chief of Staff; in the Royal Households, they are responsible for everything related to the official governmental roles played by Family members. The Queen, Prince Charles, and Prince William each have one, and the ouster of Geidt (who was very defensive of the Queen's authority) was apparently led by Prince Charles' PS, Clive Alderton. The Queen's current PS, Edward Young, is seen as bit of a pushover in conflicts with Alderton, which is how Charles wants it, and the Queen has conceded because she accepts that she is unlikely to live all that much longer, and feels it appropriate to give more internal authority to Charles at this point, to ease the transition when it happens. FWIW, Princess Anne and the Earl of Wessex apparently think that Edward Young is a really poor manager who does not do enough to guard the Queen's interests; they preferred Geidt.) Anyway, back to Cohen ...
The Queen appointed Cohen to work for Meghan in November 2017, just before the engagement was publicly announced. Her role was described as "easing Ms. Markle's transition", and tutoring her on protocol was one of the major official duties, along with managing Markle's government-paid staff of 12 people. Now, this is just my opinion, but when one has a staff of 12 at one's disposal, led by someone with 17 years of Palace experience, it would seem to me that instruction and advice on how best to get things done should be pretty easy to come by if one is willing to take it.
Cohen officially left as of the end of November 2019, so her "notice period" was an entire year long. That, to me, looks like a situation where she was trying to leave, but was continually asked to stay for just a little while longer. (Cohen now is the CEO of the Commonwealth Enterprise and Investment Council.)