At this time the func is ignoring the "24-Hour Time" switch in the Settings.
That sounds like a straightforward bug to me, and I recommend that you file it as such.
Please post your bug number, just for the record.
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware
let myEmail = "eskimo" + "1" + "@apple.com"
The problem ID is 50623228.