That's what is expected; a feature not a bug. If you insist that weeks begin on <SOME WEEKDAY>, then either some of the first week of a year is in the previous

That's what is expected; a feature not a bug. If you insist that weeks begin on <SOME WEEKDAY>, then either some of the first week of a year is in the previous calendar year, or some days of the new year aren't in the first week. 365 mod 7 is not 0. Neither is 265.24 (leap years don't exist on century years).