Samoa and American Samoa are a better example, since there's a 45-minute flight between them, and a ferry.

Samoa: UTC+13, UTC+14 in the summer

American Samoa: UTC-11 all year

Where's the anomaly? Things like this are unavoidable, since wraparound must happen somewhere.

Oh right I missed that, I was still waking up. Anything up to (24h-epsilon) would be fine mathematically, but a full 24h can of course be called an anomaly.

I retract the statement, but it's too late to add this as an edit now.

But it hasn't wrapped around. Instead of wrapping back to 0 hours difference, it "kept going" to get 24 hours difference.

It’s the fact that they’re the same time but different days. If we had a sensible system then there would never be the case that two places were at the same time (i.e. 8:24pm), but on different days.

I mean timezones are very much an organic human concept in the first place. They aren’t strictly “science” or “data” but reflections of the cultures, values and politics of the humans living in them.

Any time zone system, no mater how rational and logical it’s roots are, will eventually get filled with one-offs, exceptions and crazy baggage. It’s like Unicode or any other international standard. They are complex and often logically inconsistent not because the designers are fools, but because humans are wet fuzzy meat bags.