STM32F373 RTC is accurate with VBAT but not when power is on

[DCajigal]

The RTC looses 15 min every 8 hour aprox when the main power is on. I have selected the LSE as the RTC clock, as i show in the images, and i have a 32.768 Khz 10 ppm crystal with a 9 pF load. I thought that maybe it was due to a bad match of the crystal capacitors but the RTC works fine when the main power is off! I really dont know what is going on... Thanks in advance.

[DCajigal]

In the end it really seems like a hardware problem. The MCO output is not stable when i turn on or off some peripherals...So i will try to be more careful with the RTC in the next design and see if the problem dissapears. Thanks for the help

[Freedom_Neo]

Dear @DCajigal​ I have same problem. How did you solved this problem?

https://community.st.com/s/question/0D53W00001ScZorSAF/internal-rtc-clock-lag-issue