This is probably a nonstandard variant of European date order, yielding YYYY-DD-MM.
Usually when the year goes first or when there are hyphens as delimiters, it's an ISO 8601-style date (YYYY-MM-DD). However, Europeans often write DD/MM in other contexts, so the habit could transfer over when writing the year first, even though there's no standardized format that does this.
> Every country except the US (not counting the ones that use YYYY/DD/MM, such as Japan).
What? Japanese dates are always year-month-day, with slightly different separators. More generally the date notation tends to strongly reflect how it is spoken (e.g. "1st January 2023" becomes "1/1/2023") and there are enough countries where you never put day before month.
> Why does it differ between English speaking countries, then?
Because they speak differently? I would expect "November 17, 2022" spoken as "November seventeenth, twenty twenty-two" vs. "17 Nov 2022" as "seventeenth of November, twenty twenty-two". Wikipedia [1] does say that the latter DMY form recently arose possibly in order to resolve ambiguities and the spoken form is less common, but I expect it to be more frequently spoken after enough years of usage.
Usually when the year goes first or when there are hyphens as delimiters, it's an ISO 8601-style date (YYYY-MM-DD). However, Europeans often write DD/MM in other contexts, so the habit could transfer over when writing the year first, even though there's no standardized format that does this.