As we reported last week when the UK clocks fell back, there's a quirk in the iOS calendar display routines that's evident on the first day after the switch from Daylight Saving Time back to Standard Time. Although alarms and reminders trigger as they should (on the new schedule), the "red line" current time indicator in the Calendar app is showing one hour later than it should (old time).
US users are now seeing this issue, as we "fell back" last night from DST to ST and gained a replay of the 1 am – 2 am hour. This is a purely cosmetic bug and should clear up soon; it is annoying, however, and a reminder that iOS and Mac users have often struggled with more serious time-logic flaws -- alarms that go off an hour late, for instance. The moral: for the Monday after a time switch, set a second alarm clock just in case.
Thanks to everyone who sent this in.