Even after the Court Circular entry of May 29, 2019 in which she was referred to as Princess Eugenie, Mrs. Jack Brooksbank for the first time, the issue of Princess Eugenie's title has been a bit more convoluted than a supposed "change" from "of York" to "Mrs. Jack Brooksbank".
Not very long afterwards, in
the official British monarchy website's listing of members of the Royal Family, the princess's title was changed for a second time. The "Mrs. Jack Brooksbank" was taken off, but the "of York" was not restored.
THE ROYAL FAMILY
[...]
Her Royal Highness Princess Eugenie and Mr. Jack Brooksbank
The form letter sent out by her family's Assistant Private Secretary for her first wedding anniversary in October 2019 (posted on a blog) used only "of York", and not "Mrs. Jack Brooksbank".
Buckingham Palace
12th October, 2019
Dear Miss Daly,
Princess Eugenie of York and Mr. Jack Brooksbank have asked me to thank you for sending them your congratulations on their first Wedding Anniversary.
They are very grateful to you for thinking of them and send you their best wishes.
Yours Sincerely
Charlotte Fenn
Ms Charlotte Fenn
Assistant Private Secretary to HRH Princess Eugenie of York
The Royal Ascot carriage lists in June 2019 did not refer to her as "Mrs. Jack Brooksbank". Furthermore, one of the lists refers her as "of York", even though Princess Alexandra is referred to in the same list as "the Hon. Lady Ogilvy".
The art gallery where she is employed still styles her as Eugenie York, not Eugenie Brooksbank.
Director
Eugenie York
The princess continues to use HRH Princess Eugenie of York
for her anti-slavery work.
Our Team – The Anti-Slavery Collective
[...]
HRH Princess Eugenie of York
CO-FOUNDER
In the same vein, the charities she supports have continued to call her "of York" even after May 2019.
Freedom United (August 2019)
To reach people who may yet to have developed their knowledge, Freedom United is delighted to be partnering up with The Anti-Slavery Collective, which was founded by HRH Princess Eugenie
of York, and her best friend, Julia De Boinville.
The Anti-Slavery Initiative (October 2019)
Thank you, HRH Princess Eugenie
of York for agreeing to become our Patron for this, our 180th year.
The blogger who received the letter quoted above gave this opinion of the situation:
And we have seen Buckingham Palace in general drop the "of York" from Princess Eugenie's name since the wedding. But, Prince Andrew's office still insists on using it, probably because it improves name recognition.
I do not subscribe to the blogger's opinion that a woman who continues to use her own name after marriage is being "insistent", but her opinion that the Queen's office handles Eugenie's title differently than the Duke of York's office is consistent with the previous uses of Eugenie's title in the official record,
quoted in message #287.
The announcements in the Court Circular and from the Royal Household in which Princess Eugenie was referred to as "of York" related to events handled or attended by the Duke of York, while the announcements in the Court Circular in which she was referred to as "Mrs. Jack Brooksbank" related to events hosted by the Queen.
At this point my hypothesis is that Princess Eugenie's choice is to remain "of York", and her choice is respected by her father, whereas her grandmother, who
has at times pressured married women to use their husbands' names, insists on using "Mrs. Jack Brooksbank", and the seeming inconsistencies are the result of their disagreement.