Settings > Language & Regions > Date Format – not functioning correctly.

I have repeatably set the date format to how I'd like it to appear in my directory folders but the setting will not take.

As you can see in the screenshot, I have set the date format to what some refer to as a 'logical date' year month day but the change will not appear in my finder.

The date format I wish: "2025.12.19 at 12:34:031"

The date format that appears for files and documents, despite settings: "December 19, 2025 at 12:34:031"

I have attempted the reset numerous times, with a finder relaunch to insure it takes. I have also restarted the computer but nothing works. I even gave the change a day or two to see if it was an indexing issue.

No success. Am I missing something? Is this a bug?

I am a professional landscape photographer that uses a specialized system of shooting auto bracketed exposures and then merging them into single images, in the computer via software. The folders are long lists of RAW images that are separated by a hundredths of a second. It is very important for clarity and separation of sequences, that date and time formats be compact and less verbose.

You can see in the screenshot that I have set the date format to the preferred option and that the setting is being verified in the top of the window.

This used to be easy and for many years I had the computers set to my preference but when I upgraded to Sequoia it reverted to the now, current -unwanted format. Seconds went away in the time format as well, to get the hundredths setting required a prompt in the Terminal app.

I don't really understand Apple's attitude towards users now, especially professional users, they used to honor and protect user choices.

I am using Sequoia 15.4.1 (24E263) on both my MacBook Pro and my Mac Pro. Yes, the problem is on both computers.