Why the STM32L073RZ Wakes up (restarts) every 24 hours (in STANDBYMode)

I need to fix something in a project that I didn't program.

The problem occures (sometimes) after the product is restarted 24 hours after we remve it from the USB.

The project uses HAL_PWR_EnterSTANDBYMode to enter the Low level mode, but I don't see and calls to HAL_RTC_SetAlarm_IT before.

It does call HAL_RTC_SetAlarm_IT in another place for one minute (after the current time), and it ivokes its callback.

So I assume that it uses another method to wakeup, but I don't see how.