iOS17 Bug: NSCalendar compareDate:toDate:toUnitGranularity always return "same"

in iOS 17, I found the function [compareDate:toDate:toUnitGranularity] in NSCalendar always return “same” here is the code :

NSString *transformedFromDateStr = "2023-06-16";
NSString *transformedToDateStr = "2023-06-20";

NSDate *transformedFromDate = [NSDate dateWithString:transformedFromDateStr formatString:@"yyyy-MM-dd" timeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
    NSDate *transformedToDate = [NSDate dateWithString:transformedToDateStr formatString:@"yyyy-MM-dd" timeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
    
    NSCalendarUnit uint = NSCalendarUnitDay;
    NSCalendar *calendar = [NSCalendar currentCalendar];
    calendar.timeZone = [NSTimeZone timeZoneForSecondsFromGMT:0];
  
//the result  always return  true
    NSComparisonResult result = [calendar compareDate:transformedFromDate
                                               toDate:transformedToDate
                                    toUnitGranularity:uint];

now before iOS 17 is right, why this happened ?