I wonder how they missed it. If someone was asked to write verification tests for a RTC chip, this would one of the first few things obvious things to be checked.
Really, or are you just saying that? They "missed it" because either (a) they didn't bother to test at all, or (b) they actually thought November has 31 days and didn't bother to do the 4 seconds of research required to get both the implementation and the test correct (since, of course, the people writing this are almost certainly Chinese and know as much about the Gregorian calendar as they know about McDonald's hamburgers, Norman Rockwell's art, or the present value of the euro).
