Wasn’t some or part of Hawaii like that when Pearl Harbor was bombed? I seem to recall reading years ago that part of putting together the puzzle after the fact and building a timeline of events was difficult until they realized the half-hour offset thing.
As a pre-teen, the Central/Western time zone boundary in North Dakota, where I grew up, ran along the Missouri River. This meant that someone getting the kiddies off to school in Mandan at, say, the usual 7:30 am time frame, would already be late for work in Bismarck, the sister city to the east where it was 8:30 am, a popular work start time.
With some agitation, the boundary was moved a few miles to the west. This worked for the next 40 years or so when the oil boom caused some new population centers to develop and it was adjusted further to move a couple of the more populous (by North Dakota standards) counties completely into the central time zones.
So there is plenty of precedent here.