Build version @56d874c68700 202603150806 according to devtools in prod.

In Hungarian locale the date picker creates date like this: 2026.Már.23.
The dot at the end invalidates this, I believe because of UI/WebServerResources/js/Preferences/Preferences.service.js:237 where a regex filters it. This makes the preferencesForm invalid, and thus the save button remains disabled - for the entire mail settings tab, even when the date wouldn't be relevant, because the default date there is invalid too, blocking the save button for the entire tab regardless of anything.
This would be the same for any other locales where a dot is at the end of the date.

Not sure which solution is the best:

• Either modify the regex to allow the dot (but idk if there are other reasons to invalidate a dot at the end)
• or modify the datepicker and defaults to remove the dot at the end in all relevant locales. (Not sure how to do that best, I'm not a programmer.)