Hello @CCtl.1 ,
Make sure to configure properly the RTC clock source and prescaler settings. Check also the interrupt priorities.
If possible, share your code and provide more details about your hardware/software used and your configuration. This will help community users to answer you.
>>Our application needs timestamp included in every packet, so during runtime we are updating the RTC datetime.
If the RTC is WORKING, WHY do you need to keep updating it, surely it just ticks if operating normally, off the LSE crystal..