Unexpected time output in C++ program

I have a C++ program about set time, and the time output is unexpected.

When I try to print the time of an event, it consistently displays the time as 06:36 instead of the expected 00:00. I'm using the printEvent() function to print the event details, and the setDTStart() and easySetDTStart() functions to set the start time.

But when I set the parameter byTaiwan = true. The time correctly add 8 hours in the output.

I'm unsure why this discrepancy is happening and would appreciate any insights or suggestions on how to resolve this issue. Thanks.

//event.h
#ifndef UNTITLED1_EVENT_H
#define UNTITLED1_EVENT_H
#include <string>
#include <vector>
#include <chrono>

using namespace std;
class Event {
private:
    chrono::system_clock::time_point dateTimeStart;
    chrono::system_clock::time_point dateTimeEnd;
public:

    void printEvent();

    void setDTStart(chrono::system_clock::time_point timePoint, bool byTaiwan);

    void easySetDTStart(int year, int month, int day, int hour, int minute, int second, bool byTaiwan);
};
#endif //UNTITLED1_EVENT_H

//event.cpp
#include <chrono>
#include "event.h"
#include "iostream"
#include "iomanip"

using namespace std;

void Event::printEvent() {
    time_t time = chrono::system_clock::to_time_t(dateTimeStart);
    cout << "DTSTART:" << put_time(gmtime(&time),"%Y %m %d T %H %M %S") << endl;
}

void Event::setDTStart(chrono::system_clock::time_point timePoint, bool byTaiwan = true) {
    if(byTaiwan)
        timePoint += chrono::hours(8);
    dateTimeStart = timePoint;
}

void Event::easySetDTStart(int year, int month, int day, int hour, int minute, int second, bool byTaiwan = true) {
    chrono::years y{year - 1970};
    chrono::months m{month - 1};
    chrono::days d{day - 1};
    chrono::hours h{hour};
    chrono::minutes min{minute};
    chrono::seconds s{second};
    setDTStart(chrono::system_clock::time_point(y+m+d+h+min+s),byTaiwan);
}

//main.cpp
#include "event.h"

int main() {
    Event event;
    event.easySetDTStart(2000,1,1,0,0,0, false);
    event.printEvent();
    event.easySetDTStart(2000,1,1,0,0,0, true);
    event.printEvent();
}

//output
DTSTART:2000 01 01 T 06 36 00
DTSTART:2000 01 01 T 14 36 00