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When the timezone changes for daylight savings time, you either lose or gain 1 hour in that day (or whatever your local equivalent is).

Makes sense, thanks!

Except for Lord Howe Island in New South Wales, Australia, where local time changes by 30 minutes.

23hs or 25hs during DST transitions are the most obvious exception (twice a year in many many countries).

Sometimes 22hrs or 26hrs if traveling by ship.

Daylight savings, or the device is on a plane and travels through timezones.

Or, back when I was doing airborne geophysical surveying across the Fijian archipelago the plane would flit from -179 to +179 longitude a few times every hour with a potential change of a full day if being naive about time zones.

Data aquisition instrumentation needs to use a lapsed epoch (to avoid UTC leap seconds) with a calibration at start and end of projects to adjust for drift, etc.