When a “fixed” formatting string proves anything but fixed, then breaks without warning or even mention in a release note.
How Apple made changes to Foundation routines which format dates and times which can break their formatting when in 12-hour clock mode.
Why couldn’t a user specify times before 0100 and after 1300, when the DatePicker worked fine using the 24-hour clock?
Should a tool like LockRattler show times in universal (UTC) format, or adjusted to the local time zone? There is no good answer, it seems.
I have got lost, and ended up trying to set these in the Language & Region pane. Help!