MSP430FR5994: Vector Push back function not working properly

Hi, I have been trying to use the vector push back in CCS v12, with MSP430, it doesnt work properly, I get values like -12284 in the vector array after pushing back an enum. This is the sample function that utlizes it.

/**< project based include files */
#include "app_ui.h"


/**< private variable definition for file */
std::vector<uti_ui::enum_ui_events> ui::event_queue;



/**
 * @brief  Add event to the UI event queue when there is an event
 * @param  enum_ui_events new_event - new event
 * @retval None
 * @details Called from an interrupt due to a new ui event
 */
void ui::UpdateEventQueue(uti_ui::enum_ui_events new_event)
{
    uint16_t queue_size = 0;
    queue_size = ui::event_queue.size();
    if (queue_size >= 1)
    {
        for(uint16_t cou = 0; cou <= queue_size; cou++)
        {
            if (new_event == ui::event_queue[cou]) return;
        }
    }
    ui::event_queue.push_back(new_event);
}

I wish to note that this same function implemented the same way, works properly with a C2000 mcu