Почему-то значение в s_sys_uptime и s_sys_time становится значением из последнего проинициализированного

/*
* build:        Debug
* name:        PrintNFHeader()
* parameters:  PNETFLOW_HEADER
* return:      nil
*/
void PrintNFHeader(PNETFLOW_HEADER header)
{
    time_t _sys_uptime = (header->unix_secs - (header->sys_uptime / 1000));
    char* s_sys_uptime = ctime(&_sys_uptime);
    time_t _sys_time = (header->unix_secs);
    char* s_sys_time = ctime(&_sys_time);
 
    fprintf(logfile, " |- System Uptime : %s |- System Time : %s",
        s_sys_uptime, s_sys_time);
    }
}

/*
* build:        Debug
* name:        PrintNFHeader()
* parameters:  PNETFLOW_HEADER
* return:      nil
*/
void PrintNFHeader(PNETFLOW_HEADER header)
{
    char timebuf[51];
    time_t _sys_time = (nfheader->unix_secs);
    strftime(timebuf, 40, "%Y-%m-%d %T %Z\n", localtime((const time_t *)&_sys_time));
    char* s_sys_time = timebuf;
    time_t _sys_uptime = (nfheader->unix_secs - (nfheader->sys_uptime / 1000));
    strftime(timebuf, 40, "%Y-%m-%d %T %Z\n", localtime((const time_t *)&_sys_uptime));
    char* s_sys_uptime = timebuf;
        fprintf(logfile, " |- System Uptime : %s |- System Time : %s",
        s_sys_uptime, s_sys_time);
    }

    char timebuf1[51];
    char timebuf2[51];
    time_t _sys_time = (nfheader->unix_secs);
    strftime(timebuf1, 40, "%Y-%m-%d %T %Z\n", localtime((const time_t *)&_sys_time));
    char* s_sys_time = timebuf1;
    time_t _sys_uptime = (nfheader->unix_secs - (nfheader->sys_uptime / 1000));
    strftime(timebuf2, 40, "%Y-%m-%d %T %Z\n", localtime((const time_t *)&_sys_uptime));
    char* s_sys_uptime = timebuf2;

char timebuf[51];
strcpy(timebuf, ctime(&_sys_uptime));
//...