MySQL dates quiz - Answer
That was fast.
Oren wins a beer correctly answering the quiz.
Not exactly what I had in mind, but the rules didn’t say anything about googling it.
Solution:
MySQL thinks that in my time zone (Jerusalem) daylight savings time starts on March 30th every year (which is not exactly true) and on that day the clock goes from 01:59:59AM straight to 03:00:00AM. So all the datetime values between 30/3 02:00:00 and 30/3 02:59:59 are considered invalid.
Also funny how another person who ran into this thought it was quiz material.