[aparticulate]

My theory— In the UK, 24-hour is used much more in writing than in other parts of the anglosphere, but no Brit uses 24-hour in speech. I reckon the typo occurs when people have to convert from their "speaking" brain to their "writing" brain.

[zarzavat]

That and because British people are used to thinking in both systems and implicitly converting between them, they may not even notice the inconsistency. Whereas for Americans who are used to the 12 hour system, the discrepancy sticks out much more strongly.

[quickthrower2]

As a Brit and a developer who has ploughed through many a 24h format log entry, I agree!