FreeRTOS thread runs only 12 times and twice when debugging

Question

Hi, 
 I'm using nrf52 dev board on sdk version 14.0 with GCC compiler. I modified the hrs freertos example to add a simple thread with same priority as of logger thread. The new thread will just print a line and then suspend itself. The idle thread will then wake it up - just like logger thread. 
 As per my understanding, the new thread should keep on executing. But I see the print statements only 12 times. But when I debugging with gdb, the new thread is only executed twice. Afterwards, the debugger never hits the breakpoint set for the thread. When I force stopped the execution, the system is apparently executing a busy wait hoping for some interrupts } while (0 == (NVIC->ISPR[0] | NVIC->ISPR[1])); at external/freertos/portable/CMSIS/nrf52/port_cmsis_systick.c:294 
 Here is the code: 
 static void a_thread(void * arg)
{
 UNUSED_PARAMETER(arg);

 while (1)
 {
 NRF_LOG_DEBUG("Printing from the thread");
 NRF_LOG_FLUSH();

 vTaskSuspend(NULL); // Suspend myself
 }
}

void vApplicationIdleHook( void )
{
 vTaskResume(m_logger_thread);
 vTaskResume(m_a_thread);
}

int main(void)
{
 bool erase_bonds;

 clock_init();

 // Do not start any interrupt that uses system functions before system initialisation.
 // The best solution is to start the OS before any other initalisation.

 log_init();

#if NRF_LOG_ENABLED
 // Start execution.
 if (pdPASS != xTaskCreate(logger_thread, "LOGGER", 256, NULL, 1, &m_logger_thread))
 {
 APP_ERROR_HANDLER(NRF_ERROR_NO_MEM);
 }
#endif

 // Activate deep sleep mode.
 SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
 
 if (pdPASS != xTaskCreate(a_thread, "THREAD", 128, NULL, 1, &m_a_thread))
 {
 APP_ERROR_HANDLER(NRF_ERROR_NO_MEM);
 }


 // Start FreeRTOS scheduler.
 NRF_LOG_DEBUG("Starting FreeRTOS scheduler");
 NRF_LOG_FLUSH();
 vTaskStartScheduler();


 while (true)
 {
 APP_ERROR_HANDLER(NRF_ERROR_FORBIDDEN);
 }
}
 
 What could be happening? Is something wrong with freertos configuration or is it my understanding ?