Why does NSDateFormatter return nil date for these 4 time zones?

Try running this in iOS6 (haven't tested pre iOS6):

NSDateFormatter *julianDayDateFormatter = nil;
julianDayDateFormatter = [[NSDateFormatter alloc] init];
[julianDayDateFormatter setDateFormat:@"g"];

for (NSString *timeZone in [NSTimeZone knownTimeZoneNames]) {
    julianDayDateFormatter.timeZone = [NSTimeZone timeZoneWithName: timeZone];
    NSDate *date = [julianDayDateFormatter dateFromString:[NSString stringWithFormat:@"%d", 2475213]];
    if (date == nil)
        NSLog(@"timeZone = %@", timeZone);
}

and you get the following output:

America/Bahia
America/Campo_Grande
America/Cuiaba
America/Sao_Paulo

Can anyone explain why these four time zones behave like this with NSDateFormatter set to julian day numbers? All other time zones makes NSDateFormatter return actual NSDates.